Today's Message Index:
----------------------
1. 03:13 AM - Re: Flap cross tube problem (Greg Fuchs)
2. 04:59 AM - Re: Re: Ducati rectifier/regulators (Jan de Jong)
3. 06:00 AM - Re: Re: Ducati rectifier/regulators (Max Cointe (Free))
4. 07:37 AM - Re: Re: Ducati rectifier/regulators (Jan de Jong)
5. 09:31 AM - Re: Re: Ducati rectifier/regulators (Greg Fuchs)
6. 10:07 AM - Ducati rectifier/regulators ... a different perspective (nigel_graham@m-tecque.co.uk)
7. 10:38 AM - Re: Ducati rectifier/regulators ... a different perspective (Peter Zutrauen)
8. 11:14 AM - Re: Ducati rectifier/regulators ... a different perspective (David Joyce)
9. 11:33 AM - Re: Ducati rectifier/regulators ... a different perspective (houlihan)
10. 11:49 AM - Re: Ducati rectifier/regulators ... a different perspective (Peter Zutrauen)
11. 12:03 PM - Re: Re: Ducati rectifier/regulators (Jan de Jong)
12. 12:23 PM - Re: Ducati rectifier/regulators ... a different perspective (Jan de Jong)
13. 12:33 PM - Re: Ducati rectifier/regulators ... a different perspective (houlihan)
14. 01:13 PM - Re: Re: Ducati rectifier/regulators (Bill Henderson)
15. 01:22 PM - Re: Ducati rectifier/regulators ... a different perspective (Pete)
16. 01:43 PM - Re: Re: Ducati rectifier/regulators (Pete)
17. 01:49 PM - Re: Re: Ducati rectifier/regulators (Pete)
18. 02:15 PM - Re: Ducati rectifier/regulators ... a different perspective (David Joyce)
19. 05:09 PM - Re: Ducati rectifier/regulators ... a different perspective (Paul McAllister)
20. 11:54 PM - Re: Re: Ducati rectifier/regulators (Greg Fuchs)
21. 11:55 PM - Re: Ducati rectifier/regulators ... a different perspective (Greg Fuchs)
Message 1
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| Subject: | Flap cross tube problem |
This is an old issue, but I never got back to it to close it out. Once the
slots in the fuse were cut and the tube in place, it was indeed too short by
just over a half inch or so (from memory). The company sent me some longer
bearing holder's to install to the ends of the tube, and this was able to
take up the distance. So for anyone else in my shoes, this might be the
solution that works for them.
Greg
_____
From: Greg Fuchs [mailto:gregoryf.flyboy@comcast.net]
Sent: Friday, June 03, 2011 5:04 AM
Subject: Europa-List: Flap cross tube problem
Hi all,
The flap cross tube appears to be about 2 inches too short, on my aircraft!
I was hoping there would be some end pieces placed onto FL15 to lengthen it,
but unfortunately, the GE12 bearing and the bearing holder do not increase
the length. There does not appear to be any way it will be long enough to
firmly grab the pins on both flaps, though it might just be able to span the
gap to barely reach the in-board ends of the pins. The length of my flap
cross tube (FL15) is 44 and one half inches from end to end. Can someone
tell me what theirs measures? Anyone have this problem?
Thank you,
Greg A050
Message 2
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| Subject: | Re: Ducati rectifier/regulators |
Equally respectfully - "dumping to ground" is not dumping, but
connection to the negative DC output terminal.
I attach a little OpenOffice drawing that hopefully clarifies (I hope
that works).
Regards,
Jan
On 1/20/2014 11:21 PM, Greg Fuchs wrote:
>
> Respectfully, I believe that the circuit configuration that you are thinking
> of is incorrect, Jan de Jong.
>
> The SCR's do EXACTLY 'dump' the AC output DIRECTLY to ground.
> When one end of the thyristor connects to the alternating current output of
> the coil, and the other end to ground...then that is all they can do but
> short the AC output to ground. It is not acting as a PWM-like device at all,
> simply a grounding device. Call it a direct-connect.
>
> You mention heat. The direct-connect method is the best way to deal with the
> heat. The forward voltage drop of the 'dumping' device is low, and the
> current does not need to go through the diodes at all, which are
> bypassed...hence your lowest heat output.
>
> Since the 'dumping device' connects the alternator output directly to
> ground, without going through the diode, what is the power dissipated? While
> in the dumping mode, lets say the current to dump was 10 amps(I'll use your
> generously supplied information, so I don't have to look up specs) it would
> be 1.1V * 10 amps. That's it. 11 watts. That is much better than the 18
> Watts in your configuration.
>
>> (
>> a failure mode for the Ducati device is reportedly the loss of continuity
> of a diode pill attachment through thermal >cycling; fitting external
> parallel diodes has been proposed as a solution; replacing the whole device
> seems more
>> sensible
>> )
> Well, maybe so! However, if the failure mode is a loss in continuity, that
> would mean the diodes are opening. That would also mean that connecting the
> external diodes to the regulator would bring it back to life!
>
> Regards,
> Greg
>
>
> -----Original Message-----
> From: owner-europa-list-server@matronics.com
> [mailto:owner-europa-list-server@matronics.com] On Behalf Of Jan de Jong
> Sent: Monday, January 20, 2014 7:40 AM
> To: europa-list@matronics.com
> Subject: Re: Europa-List: Re: Ducati rectifier/regulators
>
>
> Re two-phase bridge rectifier/regulator.
> The 2 thyristors in the rectifier bridge do not short the AC input or "dump"
> anything.
> On the contrary, they disconnect the DC output from the AC input when the
> output voltage threatens to exceed the set voltage.
> All output current passes through one branch of one diode and one thyristor
> in series half the time and through the other identical branch also half the
> time.
> Heat development is proportional to the output current and the voltage drop
> across a branch.
> Voltage drops increase somewhat with current, so heat development increases
> more than linearly with output current.
> In the Ducati device the diode is reportedly a MR2510 pill (typically 0.75V
> at 10A, 0.8V at 20A), the thyristor can be a 2N6504 (typically 1.1V at 10A,
> 1.3V at 20A).
> So at 10A the two branches of the bridge are each expected to generate
> 0.5 x (7.5 + 11) = 9.25W (total 18.5W) of heat.
> And at 20A the two branches of the bridge are each expected to generate
> 0.5 x (16 + 26) = 21W (total 42W) of heat.
>
> (
> a failure mode for the Ducati device is reportedly the loss of continuity of
> a diode pill attachment through thermal cycling; fitting external parallel
> diodes has been proposed as a solution; replacing the whole device seems
> more sensible
> )
>
> Cheers,
> Jan de Jong
>
Message 3
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| Subject: | Re: Ducati rectifier/regulators |
Hi There,
Excuse my french but as far as I remember from my initial training in
electronics (in the 70's) a bridge of diodes will transform AC
input(sinusoidal signal) in semi-sinusoid output which will be "transformed"
in DC voltage by the action of a capacity. That DC output will be
proportional in value to the input which is itself proportional to value of
RPM of the alternator and to the consumption. At the output of the bridge is
the input of the regulator which will act to maintain constant its own DC
output, more precisely to regulator the output DC current so that the output
DC voltage is at a standard level defined to have the battery correctly
charged ie 14.5V for the SH and 13.8V for the Ducati.
My two cents
Max Cointe
mcointe@free.fr
F-PMLH Europa XS_TriGear
Kit #560-2003 912ULS/AirmasterAP332 490 hours
F-PLDJ DynAro MCR 4S
Kit #27-2002 912ULSFR/MTProp MTV7A 1600 heures
-----Message d'origine-----
De: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] De la part de Jan de Jong
Envoy: mardi 21 janvier 2014 13:59
: europa-list@matronics.com
Objet: Re: Europa-List: Re: Ducati rectifier/regulators
Equally respectfully - "dumping to ground" is not dumping, but connection to
the negative DC output terminal.
I attach a little OpenOffice drawing that hopefully clarifies (I hope that
works).
Regards,
Jan
On 1/20/2014 11:21 PM, Greg Fuchs wrote:
> --> <gregoryf.flyboy@comcast.net>
>
> Respectfully, I believe that the circuit configuration that you are
> thinking of is incorrect, Jan de Jong.
>
> The SCR's do EXACTLY 'dump' the AC output DIRECTLY to ground.
> When one end of the thyristor connects to the alternating current
> output of the coil, and the other end to ground...then that is all
> they can do but short the AC output to ground. It is not acting as a
> PWM-like device at all, simply a grounding device. Call it a
direct-connect.
>
> You mention heat. The direct-connect method is the best way to deal
> with the heat. The forward voltage drop of the 'dumping' device is
> low, and the current does not need to go through the diodes at all,
> which are bypassed...hence your lowest heat output.
>
> Since the 'dumping device' connects the alternator output directly to
> ground, without going through the diode, what is the power dissipated?
> While in the dumping mode, lets say the current to dump was 10
> amps(I'll use your generously supplied information, so I don't have to
> look up specs) it would be 1.1V * 10 amps. That's it. 11 watts. That
> is much better than the 18 Watts in your configuration.
>
>> (
>> a failure mode for the Ducati device is reportedly the loss of
>> continuity
> of a diode pill attachment through thermal >cycling; fitting external
> parallel diodes has been proposed as a solution; replacing the whole
> device seems more
>> sensible
>> )
> Well, maybe so! However, if the failure mode is a loss in continuity,
> that would mean the diodes are opening. That would also mean that
> connecting the external diodes to the regulator would bring it back to
life!
>
> Regards,
> Greg
>
>
> -----Original Message-----
> From: owner-europa-list-server@matronics.com
> [mailto:owner-europa-list-server@matronics.com] On Behalf Of Jan de
> Jong
> Sent: Monday, January 20, 2014 7:40 AM
> To: europa-list@matronics.com
> Subject: Re: Europa-List: Re: Ducati rectifier/regulators
>
>
> Re two-phase bridge rectifier/regulator.
> The 2 thyristors in the rectifier bridge do not short the AC input or
"dump"
> anything.
> On the contrary, they disconnect the DC output from the AC input when
> the output voltage threatens to exceed the set voltage.
> All output current passes through one branch of one diode and one
> thyristor in series half the time and through the other identical
> branch also half the time.
> Heat development is proportional to the output current and the voltage
> drop across a branch.
> Voltage drops increase somewhat with current, so heat development
> increases more than linearly with output current.
> In the Ducati device the diode is reportedly a MR2510 pill (typically
> 0.75V at 10A, 0.8V at 20A), the thyristor can be a 2N6504 (typically
> 1.1V at 10A, 1.3V at 20A).
> So at 10A the two branches of the bridge are each expected to generate
> 0.5 x (7.5 + 11) = 9.25W (total 18.5W) of heat.
> And at 20A the two branches of the bridge are each expected to
> generate
> 0.5 x (16 + 26) = 21W (total 42W) of heat.
>
> (
> a failure mode for the Ducati device is reportedly the loss of
> continuity of a diode pill attachment through thermal cycling; fitting
> external parallel diodes has been proposed as a solution; replacing
> the whole device seems more sensible
> )
>
> Cheers,
> Jan de Jong
>
Message 4
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| Subject: | Re: Ducati rectifier/regulators |
It is called a rectifier-regulator because the rectifier (the bridge)
also does the regulating; there is no separate regulating stage.
Two of the four diodes of the bridge are replaced by a diode-cum-switch
(a thyristor) to make that possible.
At the beginning of a phase the thyristor in the conducting branch does
not conduct.
The switch control function switches the thyristor on with a delay that
depends on input AC voltage (RPM) and output DC current (load).
It increases / decreases the delay when the (average) output DC voltage
is too high / too low.
The delay would probably be best controlled in terms of phase angle but
in practice is most likely done in terms of time.
https://en.wikipedia.org/wiki/Rectifier has a nice animation half way
the page.
The DC-output is extremely noisy - more than14V peak-to-peak for a 14V
DC average output. A large capacitor across the DC output terminals is
generally prescribed.
Regards,
Jan
On 1/21/2014 2:59 PM, Max Cointe (Free) wrote:
>
> Hi There,
>
> Excuse my french but as far as I remember from my initial training in
> electronics (in the 70's) a bridge of diodes will transform AC
> input(sinusoidal signal) in semi-sinusoid output which will be "transformed"
> in DC voltage by the action of a capacity. That DC output will be
> proportional in value to the input which is itself proportional to value of
> RPM of the alternator and to the consumption. At the output of the bridge is
> the input of the regulator which will act to maintain constant its own DC
> output, more precisely to regulator the output DC current so that the output
> DC voltage is at a standard level defined to have the battery correctly
> charged ie 14.5V for the SH and 13.8V for the Ducati.
> My two cents
>
> Max Cointe
> mcointe@free.fr
> F-PMLH Europa XS_TriGear
> Kit #560-2003 912ULS/AirmasterAP332 490 hours
>
> F-PLDJ DynAro MCR 4S
> Kit #27-2002 912ULSFR/MTProp MTV7A 1600 heures
>
>
> -----Message d'origine-----
> De : owner-europa-list-server@matronics.com
> [mailto:owner-europa-list-server@matronics.com] De la part de Jan de Jong
> Envoy : mardi 21 janvier 2014 13:59
> : europa-list@matronics.com
> Objet : Re: Europa-List: Re: Ducati rectifier/regulators
>
> Equally respectfully - "dumping to ground" is not dumping, but connection to
> the negative DC output terminal.
> I attach a little OpenOffice drawing that hopefully clarifies (I hope that
> works).
>
> Regards,
> Jan
>
> On 1/20/2014 11:21 PM, Greg Fuchs wrote:
>> --> <gregoryf.flyboy@comcast.net>
>>
>> Respectfully, I believe that the circuit configuration that you are
>> thinking of is incorrect, Jan de Jong.
>>
>> The SCR's do EXACTLY 'dump' the AC output DIRECTLY to ground.
>> When one end of the thyristor connects to the alternating current
>> output of the coil, and the other end to ground...then that is all
>> they can do but short the AC output to ground. It is not acting as a
>> PWM-like device at all, simply a grounding device. Call it a
> direct-connect.
>>
>> You mention heat. The direct-connect method is the best way to deal
>> with the heat. The forward voltage drop of the 'dumping' device is
>> low, and the current does not need to go through the diodes at all,
>> which are bypassed...hence your lowest heat output.
>>
>> Since the 'dumping device' connects the alternator output directly to
>> ground, without going through the diode, what is the power dissipated?
>> While in the dumping mode, lets say the current to dump was 10
>> amps(I'll use your generously supplied information, so I don't have to
>> look up specs) it would be 1.1V * 10 amps. That's it. 11 watts. That
>> is much better than the 18 Watts in your configuration.
>>
>>> (
>>> a failure mode for the Ducati device is reportedly the loss of
>>> continuity
>> of a diode pill attachment through thermal >cycling; fitting external
>> parallel diodes has been proposed as a solution; replacing the whole
>> device seems more
>>> sensible
>>> )
>> Well, maybe so! However, if the failure mode is a loss in continuity,
>> that would mean the diodes are opening. That would also mean that
>> connecting the external diodes to the regulator would bring it back to
> life!
>> Regards,
>> Greg
>>
>>
>>
>> -----Original Message-----
>> From: owner-europa-list-server@matronics.com
>> [mailto:owner-europa-list-server@matronics.com] On Behalf Of Jan de
>> Jong
>> Sent: Monday, January 20, 2014 7:40 AM
>> To: europa-list@matronics.com
>> Subject: Re: Europa-List: Re: Ducati rectifier/regulators
>>
>>
>> Re two-phase bridge rectifier/regulator.
>> The 2 thyristors in the rectifier bridge do not short the AC input or
> "dump"
>> anything.
>> On the contrary, they disconnect the DC output from the AC input when
>> the output voltage threatens to exceed the set voltage.
>> All output current passes through one branch of one diode and one
>> thyristor in series half the time and through the other identical
>> branch also half the time.
>> Heat development is proportional to the output current and the voltage
>> drop across a branch.
>> Voltage drops increase somewhat with current, so heat development
>> increases more than linearly with output current.
>> In the Ducati device the diode is reportedly a MR2510 pill (typically
>> 0.75V at 10A, 0.8V at 20A), the thyristor can be a 2N6504 (typically
>> 1.1V at 10A, 1.3V at 20A).
>> So at 10A the two branches of the bridge are each expected to generate
>> 0.5 x (7.5 + 11) = 9.25W (total 18.5W) of heat.
>> And at 20A the two branches of the bridge are each expected to
>> generate
>> 0.5 x (16 + 26) = 21W (total 42W) of heat.
>>
>> (
>> a failure mode for the Ducati device is reportedly the loss of
>> continuity of a diode pill attachment through thermal cycling; fitting
>> external parallel diodes has been proposed as a solution; replacing
>> the whole device seems more sensible
>> )
>>
>> Cheers,
>> Jan de Jong
>>
>
>
Message 5
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| Subject: | Re: Ducati rectifier/regulators |
Well, since the generator is not a two-legged 'phi' connection (i.e. the
midpoint of the generator coil connected to the ground of the system or
vehicle, then 'dumping to ground' may not be the term to use after all. Yes,
I think that is correct.
Here are the two main failure modes of the Ducatti regulator as I see it..
A) If the aircraft has a very low load usage (i.e. no lights, no
instruments, etc.), the scr's are stressed and 'may' fail eventually. If
this happens, the Ducatti is unrecoverable.
B) If the aircraft has a very high load usage (using up most of its 15-18
amps), the output diodes are stressed and probably will fail eventually,
which is backed up by historical data gathering (they fail a lot at high
loads per many forum users). The Ducatti would then be recoverable by
placing 25 Amp or higher diodes on the external terminals as referenced
earlier.
Scenario (A) is unlikely, since everyone likes power-hungry instruments and
the like, where scenario (B) is the most likely for the same reason.
Thus, if someone wants to 'beef up' their ducatti, then they have the option
to place the external diodes. I guess it doesn't matter what kind, as long
as they can withstand the current from the generator. They will either help
the internal diodes survive almost forever, or take over for them when they
fail (It depends on the turn-on points between the internal and external
diodes).
Jan, do you agree with this?
Best Regards,
Greg
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Jan de Jong
Sent: Tuesday, January 21, 2014 4:59 AM
Subject: Re: Europa-List: Re: Ducati rectifier/regulators
Equally respectfully - "dumping to ground" is not dumping, but connection to
the negative DC output terminal.
I attach a little OpenOffice drawing that hopefully clarifies (I hope that
works).
Regards,
Jan
On 1/20/2014 11:21 PM, Greg Fuchs wrote:
> --> <gregoryf.flyboy@comcast.net>
>
> Respectfully, I believe that the circuit configuration that you are
> thinking of is incorrect, Jan de Jong.
>
> The SCR's do EXACTLY 'dump' the AC output DIRECTLY to ground.
> When one end of the thyristor connects to the alternating current
> output of the coil, and the other end to ground...then that is all
> they can do but short the AC output to ground. It is not acting as a
> PWM-like device at all, simply a grounding device. Call it a
direct-connect.
>
> You mention heat. The direct-connect method is the best way to deal
> with the heat. The forward voltage drop of the 'dumping' device is
> low, and the current does not need to go through the diodes at all,
> which are bypassed...hence your lowest heat output.
>
> Since the 'dumping device' connects the alternator output directly to
> ground, without going through the diode, what is the power dissipated?
> While in the dumping mode, lets say the current to dump was 10
> amps(I'll use your generously supplied information, so I don't have to
> look up specs) it would be 1.1V * 10 amps. That's it. 11 watts. That
> is much better than the 18 Watts in your configuration.
>
>> (
>> a failure mode for the Ducati device is reportedly the loss of
>> continuity
> of a diode pill attachment through thermal >cycling; fitting external
> parallel diodes has been proposed as a solution; replacing the whole
> device seems more
>> sensible
>> )
> Well, maybe so! However, if the failure mode is a loss in continuity,
> that would mean the diodes are opening. That would also mean that
> connecting the external diodes to the regulator would bring it back to
life!
>
> Regards,
> Greg
>
>
> -----Original Message-----
> From: owner-europa-list-server@matronics.com
> [mailto:owner-europa-list-server@matronics.com] On Behalf Of Jan de
> Jong
> Sent: Monday, January 20, 2014 7:40 AM
> To: europa-list@matronics.com
> Subject: Re: Europa-List: Re: Ducati rectifier/regulators
>
>
> Re two-phase bridge rectifier/regulator.
> The 2 thyristors in the rectifier bridge do not short the AC input or
"dump"
> anything.
> On the contrary, they disconnect the DC output from the AC input when
> the output voltage threatens to exceed the set voltage.
> All output current passes through one branch of one diode and one
> thyristor in series half the time and through the other identical
> branch also half the time.
> Heat development is proportional to the output current and the voltage
> drop across a branch.
> Voltage drops increase somewhat with current, so heat development
> increases more than linearly with output current.
> In the Ducati device the diode is reportedly a MR2510 pill (typically
> 0.75V at 10A, 0.8V at 20A), the thyristor can be a 2N6504 (typically
> 1.1V at 10A, 1.3V at 20A).
> So at 10A the two branches of the bridge are each expected to generate
> 0.5 x (7.5 + 11) = 9.25W (total 18.5W) of heat.
> And at 20A the two branches of the bridge are each expected to
> generate
> 0.5 x (16 + 26) = 21W (total 42W) of heat.
>
> (
> a failure mode for the Ducati device is reportedly the loss of
> continuity of a diode pill attachment through thermal cycling; fitting
> external parallel diodes has been proposed as a solution; replacing
> the whole device seems more sensible
> )
>
> Cheers,
> Jan de Jong
>
Message 6
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| Subject: | Ducati rectifier/regulators ... a different perspective |
I have followed this discussion with great interest and with an
increasing sense of Dj vu.
When the issue of regulator/rectifier failures occur withing the Rotax
community, the standard fix seems to be to simply replace like with like
(at elevated Rotax pricing) and fly on until the next unit fails.
Up until about five years ago, nearly all modern Japanese motorcycles
used the same technology as that found on the Rotax 91x series engines,
permanent-magnet generators controlled by SCR rectifier/regulators. It
may come as some surprise that for an industry renowned for precision
and reliability, nearly all of these major motorcycle manufactures have
at some time, been plagued by problems with their SCR based
rectifier/regulators failing and burning out alternators and wiring,
cooking batteries and in extreme cases, squirting unregulated AC into
the wiring loom and blowing up ECUs. It was just such a failure that
"sparked" my interest :-(
Known as "Shunt Regulators" the SCR technology runs extremely hot and
requires more cooling air than modern styling and space allows.
The solution was a move towards MOSFET controlled regulators and the
numerous web-based one-make discussion groups were full of information
and advice on the reasons for failure, the benefits of the change and
practical advice on how to convert.
It was by trawling these groups that I was able to build up a good
understanding of how these R/Rs worked, what was causing the problem and
what the potential solution might be. I compiled what I considered to be
the best informed snippets of information into the attached document.
The first half gives an overview of a typical design of an SCR
Rectifier/Regulator for use on a permanent-magnet generating system and
the second half discussed the relative merrits of SCR versus MOSFET.
It would be interesting to know which technology the the after-market
Schicker and Silent-Hektic R/Rs use.
Nigel
Message 7
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| Subject: | Re: Ducati rectifier/regulators ... a different perspective |
Just as an aside......
Fwiw for my other homebuilt I added a custom tiny alternator (actually a
high-current model airplane 3-phase brushless permanent magnet "outrunner"
motor) I decided to not fully load the alternator constantly with these
wasteful regulators (in an effort to save power as well as longevity) but
instead let the rectified bus voltage climb to whatever the alternator will
produce (~27V at cruise RPM). I then use a high-frequency switching
convertor (a potted single module) to convert down to 13.4V for charging
the battery. The convertor comes on line at an input voltage > 17V. Seems
to work well so far.
Cheers,
Pete
A239
On Tue, Jan 21, 2014 at 1:06 PM, nigel_graham@m-tecque.co.uk <
nigel_graham@m-tecque.co.uk> wrote:
>
> I have followed this discussion with great interest and with an increasin
g
> sense of D=C3=A9j=C4=85 vu.
> When the issue of regulator/rectifier failures occur withing the Rotax
> community, the standard fix seems to be to simply replace like with like
> (at elevated Rotax pricing) and fly on until the next unit fails.
>
> Up until about five years ago, nearly all modern Japanese motorcycles use
d
> the same technology as that found on the Rotax 91x series engines,
> permanent-magnet generators controlled by SCR rectifier/regulators. It m
ay
> come as some surprise that for an industry renowned for precision and
> reliability, nearly all of these major motorcycle manufactures have at so
me
> time, been plagued by problems with their SCR based rectifier/regulators
> failing and burning out alternators and wiring, cooking batteries and in
> extreme cases, squirting unregulated AC into the wiring loom and blowing
up
> ECUs. It was just such a failure that "sparked" my interest :-(
>
> Known as "Shunt Regulators" the SCR technology runs extremely hot and
> requires more cooling air than modern styling and space allows.
> The solution was a move towards MOSFET controlled regulators and the
> numerous web-based one-make discussion groups were full of information an
d
> advice on the reasons for failure, the benefits of the change and practic
al
> advice on how to convert.
>
> It was by trawling these groups that I was able to build up a good
> understanding of how these R/Rs worked, what was causing the problem and
> what the potential solution might be. I compiled what I considered to be
> the best informed snippets of information into the attached document.
> The first half gives an overview of a typical design of an SCR
> Rectifier/Regulator for use on a permanent-magnet generating system and t
he
> second half discussed the relative merrits of SCR versus MOSFET.
>
> It would be interesting to know which technology the the after-market
> Schicker and Silent-Hektic R/Rs use.
>
> Nigel
>
Message 8
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| Subject: | Re: Ducati rectifier/regulators ... a different perspective |
Nigel, Fascinating and impressively erudite. You have
totally convinced me that the way all new builders should
go is with a Mofset bit of kit. However my personal
solution is to take the odd Ducatti at sale price off
anyone not planning to fit them and fly with a spare! In
1000hrs I have had one failure. That was inconveniently
1/3 way between Holland and Clacton, but there was enough
juice in the battery to get me all the way home with a bit
of thoughtful systems management. I currently fly with
Rowland's spurned new Ducatti in my spares department
under pax seat, but am prepared to offer a modest price
for another unwanted Ducatti!
Regards, David
On Tue, 21 Jan 2014 18:06:24 +0000
"nigel_graham@m-tecque.co.uk"
<nigel_graham@m-tecque.co.uk> wrote:
>
> I have followed this discussion with great interest and
>with an increasing sense of Dj vu.
> When the issue of regulator/rectifier failures occur
>withing the Rotax community, the standard fix seems to be
>to simply replace like with like (at elevated Rotax
>pricing) and fly on until the next unit fails.
>
> Up until about five years ago, nearly all modern
>Japanese motorcycles used the same technology as that
>found on the Rotax 91x series engines, permanent-magnet
>generators controlled by SCR rectifier/regulators. It may
>come as some surprise that for an industry renowned for
>precision and reliability, nearly all of these major
>motorcycle manufactures have at some time, been plagued
>by problems with their SCR based rectifier/regulators
>failing and burning out alternators and wiring, cooking
>batteries and in extreme cases, squirting unregulated AC
>into the wiring loom and blowing up ECUs. It was just
>such a failure that "sparked" my interest :-(
>
> Known as "Shunt Regulators" the SCR technology runs
>extremely hot and requires more cooling air than modern
>styling and space allows.
> The solution was a move towards MOSFET controlled
>regulators and the numerous web-based one-make discussion
>groups were full of information and advice on the reasons
>for failure, the benefits of the change and practical
>advice on how to convert.
>
> It was by trawling these groups that I was able to build
>up a good understanding of how these R/Rs worked, what
>was causing the problem and what the potential solution
>might be. I compiled what I considered to be the best
>informed snippets of information into the attached
>document.
> The first half gives an overview of a typical design of
>an SCR Rectifier/Regulator for use on a permanent-magnet
>generating system and the second half discussed the
>relative merrits of SCR versus MOSFET.
>
> It would be interesting to know which technology the the
>after-market Schicker and Silent-Hektic R/Rs use.
>
> Nigel
Message 9
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| Subject: | Re: Ducati rectifier/regulators ... a different perspective |
Hi David.
One thing to bear in mind is that there are, as I understand it, several
modes of failure of the Ducatti unit the most benign being that it just
stops charging the battery and feeding the services.
This is as you describe and as I also suffered ( why does this happen mid
channel?) but I believe it can fail and possibly allow high voltage DC or
AC onto the bus giving your expensive radio and other clever stuff a real
hard time !
In the UK there is very little difference in cost between the Schicke and
the Ducatti they are very similar in size and the wiring is only slightly
changed , one wire not connected, and the generator fail light has to
become an LED.
Tim
On 21 January 2014 19:13, David Joyce <davidjoyce@doctors.org.uk> wrote:
> davidjoyce@doctors.org.uk>
>
>
> Nigel, Fascinating and impressively erudite. You have totally convinced m
e
> that the way all new builders should go is with a Mofset bit of kit.
> However my personal solution is to take the odd Ducatti at sale price of
f
> anyone not planning to fit them and fly with a spare! In 1000hrs I have h
ad
> one failure. That was inconveniently 1/3 way between Holland and Clacton,
> but there was enough juice in the battery to get me all the way home with
a
> bit of thoughtful systems management. I currently fly with Rowland's
> spurned new Ducatti in my spares department under pax seat, but am prepar
ed
> to offer a modest price for another unwanted Ducatti!
> Regards, David
>
> On Tue, 21 Jan 2014 18:06:24 +0000
> "nigel_graham@m-tecque.co.uk" <nigel_graham@m-tecque.co.uk> wrote:
>
>>
>> I have followed this discussion with great interest and with an
>> increasing sense of D=E9j=E0 vu.
>> When the issue of regulator/rectifier failures occur withing the Rotax
>> community, the standard fix seems to be to simply replace like with like
>> (at elevated Rotax pricing) and fly on until the next unit fails.
>>
>> Up until about five years ago, nearly all modern Japanese motorcycles
>> used the same technology as that found on the Rotax 91x series engines,
>> permanent-magnet generators controlled by SCR rectifier/regulators. It
may
>> come as some surprise that for an industry renowned for precision and
>> reliability, nearly all of these major motorcycle manufactures have at s
ome
>> time, been plagued by problems with their SCR based rectifier/regulators
>> failing and burning out alternators and wiring, cooking batteries and in
>> extreme cases, squirting unregulated AC into the wiring loom and blowing
up
>> ECUs. It was just such a failure that "sparked" my interest :-(
>>
>> Known as "Shunt Regulators" the SCR technology runs extremely hot and
>> requires more cooling air than modern styling and space allows.
>> The solution was a move towards MOSFET controlled regulators and the
>> numerous web-based one-make discussion groups were full of information a
nd
>> advice on the reasons for failure, the benefits of the change and practi
cal
>> advice on how to convert.
>>
>> It was by trawling these groups that I was able to build up a good
>> understanding of how these R/Rs worked, what was causing the problem and
>> what the potential solution might be. I compiled what I considered to be
>> the best informed snippets of information into the attached document.
>> The first half gives an overview of a typical design of an SCR
>> Rectifier/Regulator for use on a permanent-magnet generating system and
the
>> second half discussed the relative merrits of SCR versus MOSFET.
>>
>> It would be interesting to know which technology the the after-market
>> Schicker and Silent-Hektic R/Rs use.
>>
>> Nigel
>>
>
===========
===========
===========
===========
>
>
Message 10
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| Subject: | Re: Ducati rectifier/regulators ... a different perspective |
"allow high voltage" .... hopefully the battery would do it's best to soak
it up (with the alternator's limited current generating capacity).
Cheers,
Pete
On Tue, Jan 21, 2014 at 2:31 PM, houlihan <houlihan@blueyonder.co.uk> wrote
:
> Hi David.
>
> One thing to bear in mind is that there are, as I understand it, several
> modes of failure of the Ducatti unit the most benign being that it just
> stops charging the battery and feeding the services.
> This is as you describe and as I also suffered ( why does this happen mid
> channel?) but I believe it can fail and possibly allow high voltage DC or
> AC onto the bus giving your expensive radio and other clever stuff a real
> hard time !
>
> In the UK there is very little difference in cost between the Schicke and
> the Ducatti they are very similar in size and the wiring is only slightl
y
> changed , one wire not connected, and the generator fail light has to
> become an LED.
>
> Tim
>
>
> On 21 January 2014 19:13, David Joyce <davidjoyce@doctors.org.uk> wrote:
>
>> davidjoyce@doctors.org.uk>
>>
>>
>> Nigel, Fascinating and impressively erudite. You have totally convinced
>> me that the way all new builders should go is with a Mofset bit of kit.
>> However my personal solution is to take the odd Ducatti at sale price o
ff
>> anyone not planning to fit them and fly with a spare! In 1000hrs I have
had
>> one failure. That was inconveniently 1/3 way between Holland and Clacton
,
>> but there was enough juice in the battery to get me all the way home wit
h a
>> bit of thoughtful systems management. I currently fly with Rowland's
>> spurned new Ducatti in my spares department under pax seat, but am prepa
red
>> to offer a modest price for another unwanted Ducatti!
>> Regards, David
>>
>> On Tue, 21 Jan 2014 18:06:24 +0000
>> "nigel_graham@m-tecque.co.uk" <nigel_graham@m-tecque.co.uk> wrote:
>>
>>>
>>> I have followed this discussion with great interest and with an
>>> increasing sense of D=E9j=E0 vu.
>>> When the issue of regulator/rectifier failures occur withing the Rotax
>>> community, the standard fix seems to be to simply replace like with lik
e
>>> (at elevated Rotax pricing) and fly on until the next unit fails.
>>>
>>> Up until about five years ago, nearly all modern Japanese motorcycles
>>> used the same technology as that found on the Rotax 91x series engines,
>>> permanent-magnet generators controlled by SCR rectifier/regulators. It
may
>>> come as some surprise that for an industry renowned for precision and
>>> reliability, nearly all of these major motorcycle manufactures have at
some
>>> time, been plagued by problems with their SCR based rectifier/regulator
s
>>> failing and burning out alternators and wiring, cooking batteries and i
n
>>> extreme cases, squirting unregulated AC into the wiring loom and blowin
g up
>>> ECUs. It was just such a failure that "sparked" my interest :-(
>>>
>>> Known as "Shunt Regulators" the SCR technology runs extremely hot and
>>> requires more cooling air than modern styling and space allows.
>>> The solution was a move towards MOSFET controlled regulators and the
>>> numerous web-based one-make discussion groups were full of information
and
>>> advice on the reasons for failure, the benefits of the change and pract
ical
>>> advice on how to convert.
>>>
>>> It was by trawling these groups that I was able to build up a good
>>> understanding of how these R/Rs worked, what was causing the problem an
d
>>> what the potential solution might be. I compiled what I considered to b
e
>>> the best informed snippets of information into the attached document.
>>> The first half gives an overview of a typical design of an SCR
>>> Rectifier/Regulator for use on a permanent-magnet generating system and
the
>>> second half discussed the relative merrits of SCR versus MOSFET.
>>>
>>> It would be interesting to know which technology the the after-market
>>> Schicker and Silent-Hektic R/Rs use.
>>>
>>> Nigel
>>>
>>
>> ========================
===========
>> target="_blank">http://www.matronics.com/Navigator?Europa-List
>> ========================
===========
>> http://forums.matronics.com
>> ========================
===========
>> le, List Admin.
>> ="_blank">http://www.matronics.com/contribution
>> ========================
===========
>>
>>
>>
>>
> *
>
===========
tronics.com/Navigator?Europa-List>
===========
===========
om/contribution>
===========
>
> *
>
>
Message 11
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| Subject: | Re: Ducati rectifier/regulators |
ad A:
Don't agree. The only stress would be somewhat higher reverse voltage.
The Ducati R/R is not a shunt regulator.
ad B:
Agree, but the thyristors are more stressed than the diodes. They drop a
little more voltage and dissipate more heat.
On the other hand, the custom fitting of the diode pills could be more
uncertain than the standard fitting of the thyristors (TO220 I believe).
Parallelling the diodes with external ones is possible. They would
require a heat sink. Are the failure statistics clear about the diodes?
I think it would be better to get an R/R without issues.
Regards,
Jan
On 1/21/2014 6:30 PM, Greg Fuchs wrote:
>
>
> Well, since the generator is not a two-legged 'phi' connection (i.e. the
> midpoint of the generator coil connected to the ground of the system or
> vehicle, then 'dumping to ground' may not be the term to use after all. Yes,
> I think that is correct.
>
> Here are the two main failure modes of the Ducatti regulator as I see it..
>
> A) If the aircraft has a very low load usage (i.e. no lights, no
> instruments, etc.), the scr's are stressed and 'may' fail eventually. If
> this happens, the Ducatti is unrecoverable.
>
> B) If the aircraft has a very high load usage (using up most of its 15-18
> amps), the output diodes are stressed and probably will fail eventually,
> which is backed up by historical data gathering (they fail a lot at high
> loads per many forum users). The Ducatti would then be recoverable by
> placing 25 Amp or higher diodes on the external terminals as referenced
> earlier.
>
> Scenario (A) is unlikely, since everyone likes power-hungry instruments and
> the like, where scenario (B) is the most likely for the same reason.
>
> Thus, if someone wants to 'beef up' their ducatti, then they have the option
> to place the external diodes. I guess it doesn't matter what kind, as long
> as they can withstand the current from the generator. They will either help
> the internal diodes survive almost forever, or take over for them when they
> fail (It depends on the turn-on points between the internal and external
> diodes).
>
> Jan, do you agree with this?
>
> Best Regards,
> Greg
>
> -----Original Message-----
> From: owner-europa-list-server@matronics.com
> [mailto:owner-europa-list-server@matronics.com] On Behalf Of Jan de Jong
> Sent: Tuesday, January 21, 2014 4:59 AM
> To: europa-list@matronics.com
> Subject: Re: Europa-List: Re: Ducati rectifier/regulators
>
> Equally respectfully - "dumping to ground" is not dumping, but connection to
> the negative DC output terminal.
> I attach a little OpenOffice drawing that hopefully clarifies (I hope that
> works).
>
> Regards,
> Jan
>
> On 1/20/2014 11:21 PM, Greg Fuchs wrote:
>> --> <gregoryf.flyboy@comcast.net>
>>
>> Respectfully, I believe that the circuit configuration that you are
>> thinking of is incorrect, Jan de Jong.
>>
>> The SCR's do EXACTLY 'dump' the AC output DIRECTLY to ground.
>> When one end of the thyristor connects to the alternating current
>> output of the coil, and the other end to ground...then that is all
>> they can do but short the AC output to ground. It is not acting as a
>> PWM-like device at all, simply a grounding device. Call it a
> direct-connect.
>>
>> You mention heat. The direct-connect method is the best way to deal
>> with the heat. The forward voltage drop of the 'dumping' device is
>> low, and the current does not need to go through the diodes at all,
>> which are bypassed...hence your lowest heat output.
>>
>> Since the 'dumping device' connects the alternator output directly to
>> ground, without going through the diode, what is the power dissipated?
>> While in the dumping mode, lets say the current to dump was 10
>> amps(I'll use your generously supplied information, so I don't have to
>> look up specs) it would be 1.1V * 10 amps. That's it. 11 watts. That
>> is much better than the 18 Watts in your configuration.
>>
>>> (
>>> a failure mode for the Ducati device is reportedly the loss of
>>> continuity
>> of a diode pill attachment through thermal >cycling; fitting external
>> parallel diodes has been proposed as a solution; replacing the whole
>> device seems more
>>> sensible
>>> )
>> Well, maybe so! However, if the failure mode is a loss in continuity,
>> that would mean the diodes are opening. That would also mean that
>> connecting the external diodes to the regulator would bring it back to
> life!
>> Regards,
>> Greg
>>
>>
>>
>> -----Original Message-----
>> From: owner-europa-list-server@matronics.com
>> [mailto:owner-europa-list-server@matronics.com] On Behalf Of Jan de
>> Jong
>> Sent: Monday, January 20, 2014 7:40 AM
>> To: europa-list@matronics.com
>> Subject: Re: Europa-List: Re: Ducati rectifier/regulators
>>
>>
>> Re two-phase bridge rectifier/regulator.
>> The 2 thyristors in the rectifier bridge do not short the AC input or
> "dump"
>> anything.
>> On the contrary, they disconnect the DC output from the AC input when
>> the output voltage threatens to exceed the set voltage.
>> All output current passes through one branch of one diode and one
>> thyristor in series half the time and through the other identical
>> branch also half the time.
>> Heat development is proportional to the output current and the voltage
>> drop across a branch.
>> Voltage drops increase somewhat with current, so heat development
>> increases more than linearly with output current.
>> In the Ducati device the diode is reportedly a MR2510 pill (typically
>> 0.75V at 10A, 0.8V at 20A), the thyristor can be a 2N6504 (typically
>> 1.1V at 10A, 1.3V at 20A).
>> So at 10A the two branches of the bridge are each expected to generate
>> 0.5 x (7.5 + 11) = 9.25W (total 18.5W) of heat.
>> And at 20A the two branches of the bridge are each expected to
>> generate
>> 0.5 x (16 + 26) = 21W (total 42W) of heat.
>>
>> (
>> a failure mode for the Ducati device is reportedly the loss of
>> continuity of a diode pill attachment through thermal cycling; fitting
>> external parallel diodes has been proposed as a solution; replacing
>> the whole device seems more sensible
>> )
>>
>> Cheers,
>> Jan de Jong
>>
>
>
Message 12
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| Subject: | Re: Ducati rectifier/regulators ... a different perspective |
The attached document describes shunt regulators - they would be most
likely to fail with an overvoltage result (failing shunt).
The Ducati is not a shunt regulator - just a diode bridge with
controlled time-outs for regulation - the most likely failing mode is
undervoltage (open bridge branch).
I believe Schicke and SH are the same, with possibly more robust
implementation and better cooling.
The possible advantage of replacing thyristors with MOSFETS is
potentially lower heat because of lower voltage drop. But unless you do
something clever you need 2 MOSFETs for each thyristor and an
interesting way to switch them.
Regards,
Jan de Jong
On 1/21/2014 7:06 PM, nigel_graham@m-tecque.co.uk wrote:
>
> I have followed this discussion with great interest and with an
> increasing sense of Dj vu.
> When the issue of regulator/rectifier failures occur withing the Rotax
> community, the standard fix seems to be to simply replace like with
> like (at elevated Rotax pricing) and fly on until the next unit fails.
>
> Up until about five years ago, nearly all modern Japanese motorcycles
> used the same technology as that found on the Rotax 91x series
> engines, permanent-magnet generators controlled by SCR
> rectifier/regulators. It may come as some surprise that for an
> industry renowned for precision and reliability, nearly all of these
> major motorcycle manufactures have at some time, been plagued by
> problems with their SCR based rectifier/regulators failing and burning
> out alternators and wiring, cooking batteries and in extreme cases,
> squirting unregulated AC into the wiring loom and blowing up ECUs. It
> was just such a failure that "sparked" my interest :-(
>
> Known as "Shunt Regulators" the SCR technology runs extremely hot and
> requires more cooling air than modern styling and space allows.
> The solution was a move towards MOSFET controlled regulators and the
> numerous web-based one-make discussion groups were full of information
> and advice on the reasons for failure, the benefits of the change and
> practical advice on how to convert.
>
> It was by trawling these groups that I was able to build up a good
> understanding of how these R/Rs worked, what was causing the problem
> and what the potential solution might be. I compiled what I considered
> to be the best informed snippets of information into the attached
> document.
> The first half gives an overview of a typical design of an SCR
> Rectifier/Regulator for use on a permanent-magnet generating system
> and the second half discussed the relative merrits of SCR versus MOSFET.
>
> It would be interesting to know which technology the the after-market
> Schicker and Silent-Hektic R/Rs use.
>
> Nigel
Message 13
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| Subject: | Re: Ducati rectifier/regulators ... a different perspective |
Hi Peter.
Batteries are expensive and overvolting does them no good at all
Tim
On 21 January 2014 19:49, Peter Zutrauen <peterz@zutrasoft.com> wrote:
> "allow high voltage" .... hopefully the battery would do it's best to soa
k
> it up (with the alternator's limited current generating capacity).
>
> Cheers,
> Pete
>
>
> On Tue, Jan 21, 2014 at 2:31 PM, houlihan <houlihan@blueyonder.co.uk>wrot
e:
>
>> Hi David.
>>
>> One thing to bear in mind is that there are, as I understand it, several
>> modes of failure of the Ducatti unit the most benign being that it just
>> stops charging the battery and feeding the services.
>> This is as you describe and as I also suffered ( why does this happen mi
d
>> channel?) but I believe it can fail and possibly allow high voltage DC o
r
>> AC onto the bus giving your expensive radio and other clever stuff a rea
l
>> hard time !
>>
>> In the UK there is very little difference in cost between the Schicke an
d
>> the Ducatti they are very similar in size and the wiring is only slight
ly
>> changed , one wire not connected, and the generator fail light has to
>> become an LED.
>>
>> Tim
>>
>>
>>
>> On 21 January 2014 19:13, David Joyce <davidjoyce@doctors.org.uk> wrote:
>>
>>> davidjoyce@doctors.org.uk>
>>>
>>>
>>> Nigel, Fascinating and impressively erudite. You have totally convinced
>>> me that the way all new builders should go is with a Mofset bit of kit.
>>> However my personal solution is to take the odd Ducatti at sale price
off
>>> anyone not planning to fit them and fly with a spare! In 1000hrs I have
had
>>> one failure. That was inconveniently 1/3 way between Holland and Clacto
n,
>>> but there was enough juice in the battery to get me all the way home wi
th a
>>> bit of thoughtful systems management. I currently fly with Rowland's
>>> spurned new Ducatti in my spares department under pax seat, but am prep
ared
>>> to offer a modest price for another unwanted Ducatti!
>>> Regards, David
>>>
>>> On Tue, 21 Jan 2014 18:06:24 +0000
>>> "nigel_graham@m-tecque.co.uk" <nigel_graham@m-tecque.co.uk> wrote:
>>>
>>>>
>>>> I have followed this discussion with great interest and with an
>>>> increasing sense of D=E9j=E0 vu.
>>>> When the issue of regulator/rectifier failures occur withing the Rotax
>>>> community, the standard fix seems to be to simply replace like with li
ke
>>>> (at elevated Rotax pricing) and fly on until the next unit fails.
>>>>
>>>> Up until about five years ago, nearly all modern Japanese motorcycles
>>>> used the same technology as that found on the Rotax 91x series engines
,
>>>> permanent-magnet generators controlled by SCR rectifier/regulators. I
t may
>>>> come as some surprise that for an industry renowned for precision and
>>>> reliability, nearly all of these major motorcycle manufactures have at
some
>>>> time, been plagued by problems with their SCR based rectifier/regulato
rs
>>>> failing and burning out alternators and wiring, cooking batteries and
in
>>>> extreme cases, squirting unregulated AC into the wiring loom and blowi
ng up
>>>> ECUs. It was just such a failure that "sparked" my interest :-(
>>>>
>>>> Known as "Shunt Regulators" the SCR technology runs extremely hot and
>>>> requires more cooling air than modern styling and space allows.
>>>> The solution was a move towards MOSFET controlled regulators and the
>>>> numerous web-based one-make discussion groups were full of information
and
>>>> advice on the reasons for failure, the benefits of the change and prac
tical
>>>> advice on how to convert.
>>>>
>>>> It was by trawling these groups that I was able to build up a good
>>>> understanding of how these R/Rs worked, what was causing the problem a
nd
>>>> what the potential solution might be. I compiled what I considered to
be
>>>> the best informed snippets of information into the attached document.
>>>> The first half gives an overview of a typical design of an SCR
>>>> Rectifier/Regulator for use on a permanent-magnet generating system an
d the
>>>> second half discussed the relative merrits of SCR versus MOSFET.
>>>>
>>>> It would be interesting to know which technology the the after-market
>>>> Schicker and Silent-Hektic R/Rs use.
>>>>
>>>> Nigel
>>>>
>>>
>>> =======================
============
>>> target="_blank">http://www.matronics.com/Navigator?Europa-List
>>> =======================
============
>>> http://forums.matronics.com
>>> =======================
============
>>> le, List Admin.
>>> ="_blank">http://www.matronics.com/contribution
>>> =======================
============
>>>
>>>
>>>
>>>
>> *
>>
>> arget="_blank">http://www.matronics.com/Navigator?Europa-List <http://
www.matronics.com/Navigator?Europa-List>
>> tp://forums.matronics.com <http://forums.matronics.com>
>> _blank">http://www.matronics.com/contribution <http://www.matronics.com/
contribution>
>>
>> *
>>
>>
> *
>
===========
tronics.com/Navigator?Europa-List>
===========
===========
om/contribution>
===========
>
> *
>
>
Message 14
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| Subject: | Re: Ducati rectifier/regulators |
As info.....
I opened up one of the Rotax regulators a friend gave me after a
failure. The two diodes were bad and were open so paralleling them with
external diodes does seem to be a viable option. Relatively cheap for
the cost of the diodes and a heat sink. No modification to the existing
regulator required. Attached is the fix I obtained from another
website. Just need to join the diodes to the B and two G terminals.
Just my two cents worth.....
Bill
A010 Classic Monowheel
Still building.
On 1/21/2014 3:02 PM, Jan de Jong wrote:
>
>
> ad A:
> Don't agree. The only stress would be somewhat higher reverse voltage.
> The Ducati R/R is not a shunt regulator.
>
> ad B:
> Agree, but the thyristors are more stressed than the diodes. They drop
> a little more voltage and dissipate more heat.
> On the other hand, the custom fitting of the diode pills could be more
> uncertain than the standard fitting of the thyristors (TO220 I believe).
>
> Parallelling the diodes with external ones is possible. They would
> require a heat sink. Are the failure statistics clear about the diodes?
> I think it would be better to get an R/R without issues.
>
> Regards,
> Jan
>
>
> On 1/21/2014 6:30 PM, Greg Fuchs wrote:
>> <gregoryf.flyboy@comcast.net>
>>
>>
>>
>> Well, since the generator is not a two-legged 'phi' connection (i.e. the
>> midpoint of the generator coil connected to the ground of the system or
>> vehicle, then 'dumping to ground' may not be the term to use after
>> all. Yes,
>> I think that is correct.
>>
>> Here are the two main failure modes of the Ducatti regulator as I see
>> it..
>>
>> A) If the aircraft has a very low load usage (i.e. no lights, no
>> instruments, etc.), the scr's are stressed and 'may' fail eventually. If
>> this happens, the Ducatti is unrecoverable.
>>
>> B) If the aircraft has a very high load usage (using up most of its
>> 15-18
>> amps), the output diodes are stressed and probably will fail eventually,
>> which is backed up by historical data gathering (they fail a lot at high
>> loads per many forum users). The Ducatti would then be recoverable by
>> placing 25 Amp or higher diodes on the external terminals as referenced
>> earlier.
>>
>> Scenario (A) is unlikely, since everyone likes power-hungry
>> instruments and
>> the like, where scenario (B) is the most likely for the same reason.
>>
>> Thus, if someone wants to 'beef up' their ducatti, then they have the
>> option
>> to place the external diodes. I guess it doesn't matter what kind, as
>> long
>> as they can withstand the current from the generator. They will
>> either help
>> the internal diodes survive almost forever, or take over for them
>> when they
>> fail (It depends on the turn-on points between the internal and external
>> diodes).
>>
>> Jan, do you agree with this?
>>
>> Best Regards,
>> Greg
>>
>> -----Original Message-----
>> From: owner-europa-list-server@matronics.com
>> [mailto:owner-europa-list-server@matronics.com] On Behalf Of Jan de Jong
>> Sent: Tuesday, January 21, 2014 4:59 AM
>> To: europa-list@matronics.com
>> Subject: Re: Europa-List: Re: Ducati rectifier/regulators
>>
>> Equally respectfully - "dumping to ground" is not dumping, but
>> connection to
>> the negative DC output terminal.
>> I attach a little OpenOffice drawing that hopefully clarifies (I hope
>> that
>> works).
>>
>> Regards,
>> Jan
>>
>> On 1/20/2014 11:21 PM, Greg Fuchs wrote:
>>> --> <gregoryf.flyboy@comcast.net>
>>>
>>> Respectfully, I believe that the circuit configuration that you are
>>> thinking of is incorrect, Jan de Jong.
>>>
>>> The SCR's do EXACTLY 'dump' the AC output DIRECTLY to ground.
>>> When one end of the thyristor connects to the alternating current
>>> output of the coil, and the other end to ground...then that is all
>>> they can do but short the AC output to ground. It is not acting as a
>>> PWM-like device at all, simply a grounding device. Call it a
>> direct-connect.
>>> You mention heat. The direct-connect method is the best way to deal
>>> with the heat. The forward voltage drop of the 'dumping' device is
>>> low, and the current does not need to go through the diodes at all,
>>> which are bypassed...hence your lowest heat output.
>>>
>>> Since the 'dumping device' connects the alternator output directly to
>>> ground, without going through the diode, what is the power dissipated?
>>> While in the dumping mode, lets say the current to dump was 10
>>> amps(I'll use your generously supplied information, so I don't have to
>>> look up specs) it would be 1.1V * 10 amps. That's it. 11 watts. That
>>> is much better than the 18 Watts in your configuration.
>>>
>>>> (
>>>> a failure mode for the Ducati device is reportedly the loss of
>>>> continuity
>>> of a diode pill attachment through thermal >cycling; fitting external
>>> parallel diodes has been proposed as a solution; replacing the whole
>>> device seems more
>>>> sensible
>>>> )
>>> Well, maybe so! However, if the failure mode is a loss in continuity,
>>> that would mean the diodes are opening. That would also mean that
>>> connecting the external diodes to the regulator would bring it back to
>> life!
>>> Regards,
>>> Greg
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: owner-europa-list-server@matronics.com
>>> [mailto:owner-europa-list-server@matronics.com] On Behalf Of Jan de
>>> Jong
>>> Sent: Monday, January 20, 2014 7:40 AM
>>> To: europa-list@matronics.com
>>> Subject: Re: Europa-List: Re: Ducati rectifier/regulators
>>>
>>>
>>> Re two-phase bridge rectifier/regulator.
>>> The 2 thyristors in the rectifier bridge do not short the AC input or
>> "dump"
>>> anything.
>>> On the contrary, they disconnect the DC output from the AC input when
>>> the output voltage threatens to exceed the set voltage.
>>> All output current passes through one branch of one diode and one
>>> thyristor in series half the time and through the other identical
>>> branch also half the time.
>>> Heat development is proportional to the output current and the voltage
>>> drop across a branch.
>>> Voltage drops increase somewhat with current, so heat development
>>> increases more than linearly with output current.
>>> In the Ducati device the diode is reportedly a MR2510 pill (typically
>>> 0.75V at 10A, 0.8V at 20A), the thyristor can be a 2N6504 (typically
>>> 1.1V at 10A, 1.3V at 20A).
>>> So at 10A the two branches of the bridge are each expected to generate
>>> 0.5 x (7.5 + 11) = 9.25W (total 18.5W) of heat.
>>> And at 20A the two branches of the bridge are each expected to
>>> generate
>>> 0.5 x (16 + 26) = 21W (total 42W) of heat.
>>>
>>> (
>>> a failure mode for the Ducati device is reportedly the loss of
>>> continuity of a diode pill attachment through thermal cycling; fitting
>>> external parallel diodes has been proposed as a solution; replacing
>>> the whole device seems more sensible
>>> )
>>>
>>> Cheers,
>>> Jan de Jong
>>>
>>
>>
>>
>>
>>
>
>
Message 15
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| Subject: | Re: Ducati rectifier/regulators ... a different perspective |
Agreed..... But better the battery before the radios ;-) when that terrible r
egulator design goes south. I am amazed it got certified....truly amazed.
> On Jan 21, 2014, at 3:33 PM, houlihan <houlihan@blueyonder.co.uk> wrote:
>
> Hi Peter.
>
> Batteries are expensive and overvolting does them no good at all
>
> Tim
>
>
>> On 21 January 2014 19:49, Peter Zutrauen <peterz@zutrasoft.com> wrote:
>> "allow high voltage" .... hopefully the battery would do it's best to soa
k it up (with the alternator's limited current generating capacity).
>>
>> Cheers,
>> Pete
>>
>>
>>> On Tue, Jan 21, 2014 at 2:31 PM, houlihan <houlihan@blueyonder.co.uk> wr
ote:
>>> Hi David.
>>>
>>> One thing to bear in mind is that there are, as I understand it, several
modes of failure of the Ducatti unit the most benign being that it just sto
ps charging the battery and feeding the services.
>>> This is as you describe and as I also suffered ( why does this happen mi
d channel?) but I believe it can fail and possibly allow high voltage DC or A
C onto the bus giving your expensive radio and other clever stuff a real har
d time !
>>>
>>> In the UK there is very little difference in cost between the Schicke an
d the Ducatti they are very similar in size and the wiring is only slightly
changed , one wire not connected, and the generator fail light has to becom
e an LED.
>>>
>>> Tim
>>>
>>>
>>>
>>>> On 21 January 2014 19:13, David Joyce <davidjoyce@doctors.org.uk> wrote
:
g.uk>
>>>>
>>>>
>>>> Nigel, Fascinating and impressively erudite. You have totally convinced
me that the way all new builders should go is with a Mofset bit of kit. How
ever my personal solution is to take the odd Ducatti at sale price off anyo
ne not planning to fit them and fly with a spare! In 1000hrs I have had one f
ailure. That was inconveniently 1/3 way between Holland and Clacton, but the
re was enough juice in the battery to get me all the way home with a bit of t
houghtful systems management. I currently fly with Rowland's spurned new Duc
atti in my spares department under pax seat, but am prepared to offer a mode
st price for another unwanted Ducatti!
>>>> Regards, David
>>>>
>>>> On Tue, 21 Jan 2014 18:06:24 +0000
>>>> "nigel_graham@m-tecque.co.uk" <nigel_graham@m-tecque.co.uk> wrote:
>>>>>
>>>>> I have followed this discussion with great interest and with an increa
sing sense of D=C3=A9j=C3- vu.
>>>>> When the issue of regulator/rectifier failures occur withing the Rotax
community, the standard fix seems to be to simply replace like with like (a
t elevated Rotax pricing) and fly on until the next unit fails.
>>>>>
>>>>> Up until about five years ago, nearly all modern Japanese motorcycles u
sed the same technology as that found on the Rotax 91x series engines, perm
anent-magnet generators controlled by SCR rectifier/regulators. It may come a
s some surprise that for an industry renowned for precision and reliability,
nearly all of these major motorcycle manufactures have at some time, been p
lagued by problems with their SCR based rectifier/regulators failing and bur
ning out alternators and wiring, cooking batteries and in extreme cases, squ
irting unregulated AC into the wiring loom and blowing up ECUs. It was just s
uch a failure that "sparked" my interest :-(
>>>>>
>>>>> Known as "Shunt Regulators" the SCR technology runs extremely hot and r
equires more cooling air than modern styling and space allows.
>>>>> The solution was a move towards MOSFET controlled regulators and the n
umerous web-based one-make discussion groups were full of information and ad
vice on the reasons for failure, the benefits of the change and practical ad
vice on how to convert.
>>>>>
>>>>> It was by trawling these groups that I was able to build up a good und
erstanding of how these R/Rs worked, what was causing the problem and what t
he potential solution might be. I compiled what I considered to be the best i
nformed snippets of information into the attached document.
>>>>> The first half gives an overview of a typical design of an SCR Rectifi
er/Regulator for use on a permanent-magnet generating system and the second h
alf discussed the relative merrits of SCR versus MOSFET.
>>>>>
>>>>> It would be interesting to know which technology the the after-market S
chicker and Silent-Hektic R/Rs use.
>>>>>
>>>>> Nigel
>>>>
>>>> ========================
===========
>>>> target="_blank">http://www.matronics.com/Navigator?Europa-List
>>>> ========================
===========
>>>> http://forums.matronics.com
>>>> ========================
===========
>>>> le, List Admin.
>>>> ="_blank">http://www.matronics.com/contribution
>>>> ========================
===========
>>>
>>>
>>>
>>> arget="_blank">http://www.matronics.com/Navigator?Europa-List
>>> tp://forums.matronics.com
>>> _blank">http://www.matronics.com/contribution
>>>
>>
>>
>>
>> arget="_blank">http://www.matronics.com/Navigator?Europa-List
>> tp://forums.matronics.com
>> _blank">http://www.matronics.com/contribution
>>
>
>
>
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D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
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D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3
D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3
D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>
Message 16
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| Subject: | Re: Ducati rectifier/regulators |
>From that schematic, it is indeed a simple waste/dump regulator,with the two failing
diodes being there to prevent battery from reverse feeding during the dumps.
It is pretty silly that they undersized them for rated alternator generating
current capacity. "Certified". Wow.
Cheers,
Pete
> On Jan 21, 2014, at 4:12 PM, Bill Henderson <europa10@bellsouth.net> wrote:
>
> As info.....
>
> I opened up one of the Rotax regulators a friend gave me after a failure. The
two diodes were bad and were open so paralleling them with external diodes does
seem to be a viable option. Relatively cheap for the cost of the diodes and
a heat sink. No modification to the existing regulator required. Attached
is the fix I obtained from another website. Just need to join the diodes to the
B and two G terminals.
>
> Just my two cents worth.....
>
> Bill
> A010 Classic Monowheel
> Still building.
>
>
>
>
>> On 1/21/2014 3:02 PM, Jan de Jong wrote:
>>
>>
>> ad A:
>> Don't agree. The only stress would be somewhat higher reverse voltage. The Ducati
R/R is not a shunt regulator.
>>
>> ad B:
>> Agree, but the thyristors are more stressed than the diodes. They drop a little
more voltage and dissipate more heat.
>> On the other hand, the custom fitting of the diode pills could be more uncertain
than the standard fitting of the thyristors (TO220 I believe).
>>
>> Parallelling the diodes with external ones is possible. They would require a
heat sink. Are the failure statistics clear about the diodes?
>> I think it would be better to get an R/R without issues.
>>
>> Regards,
>> Jan
>>
>>
>>> On 1/21/2014 6:30 PM, Greg Fuchs wrote:
>>>
>>>
>>>
>>> Well, since the generator is not a two-legged 'phi' connection (i.e. the
>>> midpoint of the generator coil connected to the ground of the system or
>>> vehicle, then 'dumping to ground' may not be the term to use after all. Yes,
>>> I think that is correct.
>>>
>>> Here are the two main failure modes of the Ducatti regulator as I see it..
>>>
>>> A) If the aircraft has a very low load usage (i.e. no lights, no
>>> instruments, etc.), the scr's are stressed and 'may' fail eventually. If
>>> this happens, the Ducatti is unrecoverable.
>>>
>>> B) If the aircraft has a very high load usage (using up most of its 15-18
>>> amps), the output diodes are stressed and probably will fail eventually,
>>> which is backed up by historical data gathering (they fail a lot at high
>>> loads per many forum users). The Ducatti would then be recoverable by
>>> placing 25 Amp or higher diodes on the external terminals as referenced
>>> earlier.
>>>
>>> Scenario (A) is unlikely, since everyone likes power-hungry instruments and
>>> the like, where scenario (B) is the most likely for the same reason.
>>>
>>> Thus, if someone wants to 'beef up' their ducatti, then they have the option
>>> to place the external diodes. I guess it doesn't matter what kind, as long
>>> as they can withstand the current from the generator. They will either help
>>> the internal diodes survive almost forever, or take over for them when they
>>> fail (It depends on the turn-on points between the internal and external
>>> diodes).
>>>
>>> Jan, do you agree with this?
>>>
>>> Best Regards,
>>> Greg
>>>
>>> -----Original Message-----
>>> From: owner-europa-list-server@matronics.com
>>> [mailto:owner-europa-list-server@matronics.com] On Behalf Of Jan de Jong
>>> Sent: Tuesday, January 21, 2014 4:59 AM
>>> To: europa-list@matronics.com
>>> Subject: Re: Europa-List: Re: Ducati rectifier/regulators
>>>
>>> Equally respectfully - "dumping to ground" is not dumping, but connection to
>>> the negative DC output terminal.
>>> I attach a little OpenOffice drawing that hopefully clarifies (I hope that
>>> works).
>>>
>>> Regards,
>>> Jan
>>>
>>>> On 1/20/2014 11:21 PM, Greg Fuchs wrote:
>>>> --> <gregoryf.flyboy@comcast.net>
>>>>
>>>> Respectfully, I believe that the circuit configuration that you are
>>>> thinking of is incorrect, Jan de Jong.
>>>>
>>>> The SCR's do EXACTLY 'dump' the AC output DIRECTLY to ground.
>>>> When one end of the thyristor connects to the alternating current
>>>> output of the coil, and the other end to ground...then that is all
>>>> they can do but short the AC output to ground. It is not acting as a
>>>> PWM-like device at all, simply a grounding device. Call it a
>>> direct-connect.
>>>> You mention heat. The direct-connect method is the best way to deal
>>>> with the heat. The forward voltage drop of the 'dumping' device is
>>>> low, and the current does not need to go through the diodes at all,
>>>> which are bypassed...hence your lowest heat output.
>>>>
>>>> Since the 'dumping device' connects the alternator output directly to
>>>> ground, without going through the diode, what is the power dissipated?
>>>> While in the dumping mode, lets say the current to dump was 10
>>>> amps(I'll use your generously supplied information, so I don't have to
>>>> look up specs) it would be 1.1V * 10 amps. That's it. 11 watts. That
>>>> is much better than the 18 Watts in your configuration.
>>>>
>>>>> (
>>>>> a failure mode for the Ducati device is reportedly the loss of
>>>>> continuity
>>>> of a diode pill attachment through thermal >cycling; fitting external
>>>> parallel diodes has been proposed as a solution; replacing the whole
>>>> device seems more
>>>>> sensible
>>>>> )
>>>> Well, maybe so! However, if the failure mode is a loss in continuity,
>>>> that would mean the diodes are opening. That would also mean that
>>>> connecting the external diodes to the regulator would bring it back to
>>> life!
>>>> Regards,
>>>> Greg
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: owner-europa-list-server@matronics.com
>>>> [mailto:owner-europa-list-server@matronics.com] On Behalf Of Jan de
>>>> Jong
>>>> Sent: Monday, January 20, 2014 7:40 AM
>>>> To: europa-list@matronics.com
>>>> Subject: Re: Europa-List: Re: Ducati rectifier/regulators
>>>>
>>>>
>>>> Re two-phase bridge rectifier/regulator.
>>>> The 2 thyristors in the rectifier bridge do not short the AC input or
>>> "dump"
>>>> anything.
>>>> On the contrary, they disconnect the DC output from the AC input when
>>>> the output voltage threatens to exceed the set voltage.
>>>> All output current passes through one branch of one diode and one
>>>> thyristor in series half the time and through the other identical
>>>> branch also half the time.
>>>> Heat development is proportional to the output current and the voltage
>>>> drop across a branch.
>>>> Voltage drops increase somewhat with current, so heat development
>>>> increases more than linearly with output current.
>>>> In the Ducati device the diode is reportedly a MR2510 pill (typically
>>>> 0.75V at 10A, 0.8V at 20A), the thyristor can be a 2N6504 (typically
>>>> 1.1V at 10A, 1.3V at 20A).
>>>> So at 10A the two branches of the bridge are each expected to generate
>>>> 0.5 x (7.5 + 11) = 9.25W (total 18.5W) of heat.
>>>> And at 20A the two branches of the bridge are each expected to
>>>> generate
>>>> 0.5 x (16 + 26) = 21W (total 42W) of heat.
>>>>
>>>> (
>>>> a failure mode for the Ducati device is reportedly the loss of
>>>> continuity of a diode pill attachment through thermal cycling; fitting
>>>> external parallel diodes has been proposed as a solution; replacing
>>>> the whole device seems more sensible
>>>> )
>>>>
>>>> Cheers,
>>>> Jan de Jong
>
> <Rotax Regulator Fix.doc>
Message 17
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| Subject: | Re: Ducati rectifier/regulators |
Oops and rectify... :-P
> On Jan 21, 2014, at 4:42 PM, Pete <peterz@zutrasoft.com> wrote:
>
> From that schematic, it is indeed a simple waste/dump regulator,with the two
failing diodes being there to prevent battery from reverse feeding during the
dumps. It is pretty silly that they undersized them for rated alternator generating
current capacity. "Certified". Wow.
>
> Cheers,
> Pete
>
>> On Jan 21, 2014, at 4:12 PM, Bill Henderson <europa10@bellsouth.net> wrote:
>>
>> As info.....
>>
>> I opened up one of the Rotax regulators a friend gave me after a failure. The
two diodes were bad and were open so paralleling them with external diodes
does seem to be a viable option. Relatively cheap for the cost of the diodes and
a heat sink. No modification to the existing regulator required. Attached
is the fix I obtained from another website. Just need to join the diodes to
the B and two G terminals.
>>
>> Just my two cents worth.....
>>
>> Bill
>> A010 Classic Monowheel
>> Still building.
>>
>>
>>
>>
>>> On 1/21/2014 3:02 PM, Jan de Jong wrote:
>>>
>>>
>>> ad A:
>>> Don't agree. The only stress would be somewhat higher reverse voltage. The
Ducati R/R is not a shunt regulator.
>>>
>>> ad B:
>>> Agree, but the thyristors are more stressed than the diodes. They drop a little
more voltage and dissipate more heat.
>>> On the other hand, the custom fitting of the diode pills could be more uncertain
than the standard fitting of the thyristors (TO220 I believe).
>>>
>>> Parallelling the diodes with external ones is possible. They would require
a heat sink. Are the failure statistics clear about the diodes?
>>> I think it would be better to get an R/R without issues.
>>>
>>> Regards,
>>> Jan
>>>
>>>
>>>> On 1/21/2014 6:30 PM, Greg Fuchs wrote:
>>>>
>>>>
>>>>
>>>> Well, since the generator is not a two-legged 'phi' connection (i.e. the
>>>> midpoint of the generator coil connected to the ground of the system or
>>>> vehicle, then 'dumping to ground' may not be the term to use after all. Yes,
>>>> I think that is correct.
>>>>
>>>> Here are the two main failure modes of the Ducatti regulator as I see it..
>>>>
>>>> A) If the aircraft has a very low load usage (i.e. no lights, no
>>>> instruments, etc.), the scr's are stressed and 'may' fail eventually. If
>>>> this happens, the Ducatti is unrecoverable.
>>>>
>>>> B) If the aircraft has a very high load usage (using up most of its 15-18
>>>> amps), the output diodes are stressed and probably will fail eventually,
>>>> which is backed up by historical data gathering (they fail a lot at high
>>>> loads per many forum users). The Ducatti would then be recoverable by
>>>> placing 25 Amp or higher diodes on the external terminals as referenced
>>>> earlier.
>>>>
>>>> Scenario (A) is unlikely, since everyone likes power-hungry instruments and
>>>> the like, where scenario (B) is the most likely for the same reason.
>>>>
>>>> Thus, if someone wants to 'beef up' their ducatti, then they have the option
>>>> to place the external diodes. I guess it doesn't matter what kind, as long
>>>> as they can withstand the current from the generator. They will either help
>>>> the internal diodes survive almost forever, or take over for them when they
>>>> fail (It depends on the turn-on points between the internal and external
>>>> diodes).
>>>>
>>>> Jan, do you agree with this?
>>>>
>>>> Best Regards,
>>>> Greg
>>>>
>>>> -----Original Message-----
>>>> From: owner-europa-list-server@matronics.com
>>>> [mailto:owner-europa-list-server@matronics.com] On Behalf Of Jan de Jong
>>>> Sent: Tuesday, January 21, 2014 4:59 AM
>>>> To: europa-list@matronics.com
>>>> Subject: Re: Europa-List: Re: Ducati rectifier/regulators
>>>>
>>>> Equally respectfully - "dumping to ground" is not dumping, but connection
to
>>>> the negative DC output terminal.
>>>> I attach a little OpenOffice drawing that hopefully clarifies (I hope that
>>>> works).
>>>>
>>>> Regards,
>>>> Jan
>>>>
>>>>> On 1/20/2014 11:21 PM, Greg Fuchs wrote:
>>>>> --> <gregoryf.flyboy@comcast.net>
>>>>>
>>>>> Respectfully, I believe that the circuit configuration that you are
>>>>> thinking of is incorrect, Jan de Jong.
>>>>>
>>>>> The SCR's do EXACTLY 'dump' the AC output DIRECTLY to ground.
>>>>> When one end of the thyristor connects to the alternating current
>>>>> output of the coil, and the other end to ground...then that is all
>>>>> they can do but short the AC output to ground. It is not acting as a
>>>>> PWM-like device at all, simply a grounding device. Call it a
>>>> direct-connect.
>>>>> You mention heat. The direct-connect method is the best way to deal
>>>>> with the heat. The forward voltage drop of the 'dumping' device is
>>>>> low, and the current does not need to go through the diodes at all,
>>>>> which are bypassed...hence your lowest heat output.
>>>>>
>>>>> Since the 'dumping device' connects the alternator output directly to
>>>>> ground, without going through the diode, what is the power dissipated?
>>>>> While in the dumping mode, lets say the current to dump was 10
>>>>> amps(I'll use your generously supplied information, so I don't have to
>>>>> look up specs) it would be 1.1V * 10 amps. That's it. 11 watts. That
>>>>> is much better than the 18 Watts in your configuration.
>>>>>
>>>>>> (
>>>>>> a failure mode for the Ducati device is reportedly the loss of
>>>>>> continuity
>>>>> of a diode pill attachment through thermal >cycling; fitting external
>>>>> parallel diodes has been proposed as a solution; replacing the whole
>>>>> device seems more
>>>>>> sensible
>>>>>> )
>>>>> Well, maybe so! However, if the failure mode is a loss in continuity,
>>>>> that would mean the diodes are opening. That would also mean that
>>>>> connecting the external diodes to the regulator would bring it back to
>>>> life!
>>>>> Regards,
>>>>> Greg
>>>>>
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>> From: owner-europa-list-server@matronics.com
>>>>> [mailto:owner-europa-list-server@matronics.com] On Behalf Of Jan de
>>>>> Jong
>>>>> Sent: Monday, January 20, 2014 7:40 AM
>>>>> To: europa-list@matronics.com
>>>>> Subject: Re: Europa-List: Re: Ducati rectifier/regulators
>>>>>
>>>>>
>>>>> Re two-phase bridge rectifier/regulator.
>>>>> The 2 thyristors in the rectifier bridge do not short the AC input or
>>>> "dump"
>>>>> anything.
>>>>> On the contrary, they disconnect the DC output from the AC input when
>>>>> the output voltage threatens to exceed the set voltage.
>>>>> All output current passes through one branch of one diode and one
>>>>> thyristor in series half the time and through the other identical
>>>>> branch also half the time.
>>>>> Heat development is proportional to the output current and the voltage
>>>>> drop across a branch.
>>>>> Voltage drops increase somewhat with current, so heat development
>>>>> increases more than linearly with output current.
>>>>> In the Ducati device the diode is reportedly a MR2510 pill (typically
>>>>> 0.75V at 10A, 0.8V at 20A), the thyristor can be a 2N6504 (typically
>>>>> 1.1V at 10A, 1.3V at 20A).
>>>>> So at 10A the two branches of the bridge are each expected to generate
>>>>> 0.5 x (7.5 + 11) = 9.25W (total 18.5W) of heat.
>>>>> And at 20A the two branches of the bridge are each expected to
>>>>> generate
>>>>> 0.5 x (16 + 26) = 21W (total 42W) of heat.
>>>>>
>>>>> (
>>>>> a failure mode for the Ducati device is reportedly the loss of
>>>>> continuity of a diode pill attachment through thermal cycling; fitting
>>>>> external parallel diodes has been proposed as a solution; replacing
>>>>> the whole device seems more sensible
>>>>> )
>>>>>
>>>>> Cheers,
>>>>> Jan de Jong
>>
>> <Rotax Regulator Fix.doc>
Message 18
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| Subject: | Re: Ducati rectifier/regulators ... a different perspective |
Tim, I absolutely accept that it is not ideal and could
cause more serious problems than simple lack of charge,
but one benign failure in 12 years of flying is pretty
close to acceptable reliability for me, and I enjoy
gliding anyway!
Happy Landings, David
On Tue, 21 Jan 2014 19:31:56 +0000
houlihan <houlihan@blueyonder.co.uk> wrote:
> Hi David.
>
> One thing to bear in mind is that there are, as I
>understand it, several
> modes of failure of the Ducatti unit the most benign
>being that it just
> stops charging the battery and feeding the services.
> This is as you describe and as I also suffered ( why
>does this happen mid
> channel?) but I believe it can fail and possibly allow
>high voltage DC or
> AC onto the bus giving your expensive radio and other
>clever stuff a real
> hard time !
>
> In the UK there is very little difference in cost
>between the Schicke and
> the Ducatti they are very similar in size and the
>wiring is only slightly
> changed , one wire not connected, and the generator fail
>light has to
> become an LED.
>
> Tim
>
>
>
> On 21 January 2014 19:13, David Joyce
><davidjoyce@doctors.org.uk> wrote:
>
>> davidjoyce@doctors.org.uk>
>>
>>
>> Nigel, Fascinating and impressively erudite. You have
>>totally convinced me
>> that the way all new builders should go is with a Mofset
>>bit of kit.
>> However my personal solution is to take the odd Ducatti
>>at sale price off
>> anyone not planning to fit them and fly with a spare! In
>>1000hrs I have had
>> one failure. That was inconveniently 1/3 way between
>>Holland and Clacton,
>> but there was enough juice in the battery to get me all
>>the way home with a
>> bit of thoughtful systems management. I currently fly
>>with Rowland's
>> spurned new Ducatti in my spares department under pax
>>seat, but am prepared
>> to offer a modest price for another unwanted Ducatti!
>> Regards, David
>>
>> On Tue, 21 Jan 2014 18:06:24 +0000
>> "nigel_graham@m-tecque.co.uk"
>><nigel_graham@m-tecque.co.uk> wrote:
>>
>>>
>>> I have followed this discussion with great interest and
>>>with an
>>> increasing sense of Dj vu.
>>> When the issue of regulator/rectifier failures occur
>>>withing the Rotax
>>> community, the standard fix seems to be to simply
>>>replace like with like
>>> (at elevated Rotax pricing) and fly on until the next
>>>unit fails.
>>>
>>> Up until about five years ago, nearly all modern
>>>Japanese motorcycles
>>> used the same technology as that found on the Rotax 91x
>>>series engines,
>>> permanent-magnet generators controlled by SCR
>>>rectifier/regulators. It may
>>> come as some surprise that for an industry renowned for
>>>precision and
>>> reliability, nearly all of these major motorcycle
>>>manufactures have at some
>>> time, been plagued by problems with their SCR based
>>>rectifier/regulators
>>> failing and burning out alternators and wiring, cooking
>>>batteries and in
>>> extreme cases, squirting unregulated AC into the wiring
>>>loom and blowing up
>>> ECUs. It was just such a failure that "sparked" my
>>>interest :-(
>>>
>>> Known as "Shunt Regulators" the SCR technology runs
>>>extremely hot and
>>> requires more cooling air than modern styling and space
>>>allows.
>>> The solution was a move towards MOSFET controlled
>>>regulators and the
>>> numerous web-based one-make discussion groups were full
>>>of information and
>>> advice on the reasons for failure, the benefits of the
>>>change and practical
>>> advice on how to convert.
>>>
>>> It was by trawling these groups that I was able to build
>>>up a good
>>> understanding of how these R/Rs worked, what was causing
>>>the problem and
>>> what the potential solution might be. I compiled what I
>>>considered to be
>>> the best informed snippets of information into the
>>>attached document.
>>> The first half gives an overview of a typical design of
>>>an SCR
>>> Rectifier/Regulator for use on a permanent-magnet
>>>generating system and the
>>> second half discussed the relative merrits of SCR versus
>>>MOSFET.
>>>
>>> It would be interesting to know which technology the the
>>>after-market
>>> Schicker and Silent-Hektic R/Rs use.
>>>
>>> Nigel
>>>
>>
> ===========
> ===========
> ===========
> ===========
>>
>>
>>
>>
Message 19
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| Subject: | Re: Ducati rectifier/regulators ... a different perspective |
David,
I am kinda, sorta with you on this. Mine failed the same way after 10
years, however I do have an OPV system that disconnects the alternator
from the system just in case.
I installed a GR6 once my original regulator died and went to heaven and so
far so good.
Paul
On Tue, Jan 21, 2014 at 4:15 PM, David Joyce <davidjoyce@doctors.org.uk>wro
te:
> davidjoyce@doctors.org.uk>
>
> Tim, I absolutely accept that it is not ideal and could cause more seriou
s
> problems than simple lack of charge, but one benign failure in 12 years o
f
> flying is pretty close to acceptable reliability for me, and I enjoy
> gliding anyway!
> Happy Landings, David
>
>
> On Tue, 21 Jan 2014 19:31:56 +0000
> houlihan <houlihan@blueyonder.co.uk> wrote:
>
>> Hi David.
>>
>> One thing to bear in mind is that there are, as I understand it, several
>> modes of failure of the Ducatti unit the most benign being that it just
>> stops charging the battery and feeding the services.
>> This is as you describe and as I also suffered ( why does this happen mi
d
>> channel?) but I believe it can fail and possibly allow high voltage DC o
r
>> AC onto the bus giving your expensive radio and other clever stuff a rea
l
>> hard time !
>>
>> In the UK there is very little difference in cost between the Schicke an
d
>> the Ducatti they are very similar in size and the wiring is only slight
ly
>> changed , one wire not connected, and the generator fail light has to
>> become an LED.
>>
>> Tim
>>
>>
>>
>> On 21 January 2014 19:13, David Joyce <davidjoyce@doctors.org.uk> wrote:
>>
>>> davidjoyce@doctors.org.uk>
>>>
>>>
>>> Nigel, Fascinating and impressively erudite. You have totally convinced
>>> me
>>> that the way all new builders should go is with a Mofset bit of kit.
>>> However my personal solution is to take the odd Ducatti at sale price
>>> off
>>> anyone not planning to fit them and fly with a spare! In 1000hrs I have
>>> had
>>> one failure. That was inconveniently 1/3 way between Holland and Clacto
n,
>>> but there was enough juice in the battery to get me all the way home
>>> with a
>>> bit of thoughtful systems management. I currently fly with Rowland's
>>> spurned new Ducatti in my spares department under pax seat, but am
>>> prepared
>>> to offer a modest price for another unwanted Ducatti!
>>> Regards, David
>>>
>>> On Tue, 21 Jan 2014 18:06:24 +0000
>>> "nigel_graham@m-tecque.co.uk" <nigel_graham@m-tecque.co.uk> wrote:
>>>
>>>
>>>> I have followed this discussion with great interest and with an
>>>> increasing sense of D=E9j=E0 vu.
>>>> When the issue of regulator/rectifier failures occur withing the Rotax
>>>> community, the standard fix seems to be to simply replace like with li
ke
>>>> (at elevated Rotax pricing) and fly on until the next unit fails.
>>>>
>>>> Up until about five years ago, nearly all modern Japanese motorcycles
>>>> used the same technology as that found on the Rotax 91x series engines
,
>>>> permanent-magnet generators controlled by SCR rectifier/regulators. I
t
>>>> may
>>>> come as some surprise that for an industry renowned for precision and
>>>> reliability, nearly all of these major motorcycle manufactures have at
>>>> some
>>>> time, been plagued by problems with their SCR based rectifier/regulato
rs
>>>> failing and burning out alternators and wiring, cooking batteries and
in
>>>> extreme cases, squirting unregulated AC into the wiring loom and
>>>> blowing up
>>>> ECUs. It was just such a failure that "sparked" my interest :-(
>>>>
>>>> Known as "Shunt Regulators" the SCR technology runs extremely hot and
>>>> requires more cooling air than modern styling and space allows.
>>>> The solution was a move towards MOSFET controlled regulators and the
>>>> numerous web-based one-make discussion groups were full of information
>>>> and
>>>> advice on the reasons for failure, the benefits of the change and
>>>> practical
>>>> advice on how to convert.
>>>>
>>>> It was by trawling these groups that I was able to build up a good
>>>> understanding of how these R/Rs worked, what was causing the problem a
nd
>>>> what the potential solution might be. I compiled what I considered to
be
>>>> the best informed snippets of information into the attached document.
>>>> The first half gives an overview of a typical design of an SCR
>>>> Rectifier/Regulator for use on a permanent-magnet generating system an
d
>>>> the
>>>> second half discussed the relative merrits of SCR versus MOSFET.
>>>>
>>>> It would be interesting to know which technology the the after-market
>>>> Schicker and Silent-Hektic R/Rs use.
>>>>
>>>> Nigel
>>>>
>>>>
>>> ===========
>> ===========
>> ===========
>> ===========
>>
>>>
>>>
>>>
>>>
>>>
===========
===========
===========
===========
>
>
Message 20
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| Subject: | Re: Ducati rectifier/regulators |
Bill-
It's nice to have real-world evidence of the diodes going out. That's great
detailed info on their replacement, that may come in handy for some of us,
thanks.
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Bill Henderson
Sent: Tuesday, January 21, 2014 1:13 PM
Subject: Re: Europa-List: Re: Ducati rectifier/regulators
As info.....
I opened up one of the Rotax regulators a friend gave me after a failure.
The two diodes were bad and were open so paralleling them with external
diodes does seem to be a viable option. Relatively cheap for the cost of the
diodes and a heat sink. No modification to the existing regulator required.
Attached is the fix I obtained from another website. Just need to join the
diodes to the B and two G terminals.
Just my two cents worth.....
Bill
A010 Classic Monowheel
Still building.
Message 21
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| Subject: | Ducati rectifier/regulators ... a different perspective |
What a great idea. Way to stretch the power, and keep it running cooler. I
have thought of splitting the Rotax generator in two, and using the higher
voltages to act as two independant generators. I don't think there would be
enough overhead voltage at lower speeds though.
_____
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Peter Zutrauen
Sent: Tuesday, January 21, 2014 10:38 AM
Subject: Re: Europa-List: Ducati rectifier/regulators ... a different
perspective
Just as an aside......
Fwiw for my other homebuilt I added a custom tiny alternator (actually a
high-current model airplane 3-phase brushless permanent magnet "outrunner"
motor) I decided to not fully load the alternator constantly with these
wasteful regulators (in an effort to save power as well as longevity) but
instead let the rectified bus voltage climb to whatever the alternator will
produce (~27V at cruise RPM). I then use a high-frequency switching
convertor (a potted single module) to convert down to 13.4V for charging
the battery. The convertor comes on line at an input voltage > 17V. Seems
to work well so far.
Cheers,
Pete
A239
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