Today's Message Index:
----------------------
1. 05:28 AM - Re: Re: Schematic for twin PM alternators (Robert L. Nuckolls, III)
2. 08:05 AM - Re: Re: Schematic for twin PM alternators (Robert L. Nuckolls, III)
3. 10:19 AM - Engine mount ground? (rvdave)
4. 10:24 AM - Re: Engine mount ground? (Robert L. Nuckolls, III)
5. 12:24 PM - Re: Re: Schematic for twin PM alternators (Paul Eckenroth)
6. 04:17 PM - Re: Engine mount ground? (John B)
7. 04:39 PM - Re: Engine mount ground? (Nati Niv)
8. 05:07 PM - Re: Schematic for twin PM alternators (user9253)
9. 05:24 PM - Re: Engine mount ground? (rvdave)
10. 05:39 PM - Re: Engine mount ground? (neal.george@gmail.com)
11. 05:39 PM - Re: Re: Engine mount ground? (John B)
12. 05:39 PM - Carling S700 2-3 switch failure. (Bill Bradburry)
13. 06:53 PM - Re: Re: Schematic for twin PM alternators (ashleysc@broadstripe.net)
14. 08:10 PM - Re: Carling S700 2-3 switch failure. (user9253)
15. 08:13 PM - Re: Engine mount ground? (user9253)
Message 1
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Subject: | Re: Schematic for twin PM alternators |
At 10:04 PM 1/18/2016, you wrote:
>
>Hi Joe;
>Being internally regulated, each alternator has it's own
>regulator. I think I will probably wire so that only one is in use at a time.
>Cheers!
Oops! So the design goals do not include
simultaneous exploitation of both alternators?
How do you plan to use this airplane and
how would the twin alternator installation
fit into your failure analysis?
Bob . . .
Message 2
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Subject: | Re: Schematic for twin PM alternators |
At 07:25 AM 1/19/2016, you wrote:
>At 10:04 PM 1/18/2016, you wrote:
>>
>>Hi Joe;
>>Being internally regulated, each alternator has it's own
>>regulator. I think I will probably wire so that only one is in use at a time.
>>Cheers!
>
> Oops! So the design goals do not include
> simultaneous exploitation of both alternators?
> How do you plan to use this airplane and
> how would the twin alternator installation
> fit into your failure analysis?
Subject: Re: AeroElectric-List: Re: Schematic for twin PM alternators
At 09:42 PM 1/18/2016, you wrote:
>Hi Bob;
>1. OK. Amounts to the same thing.
>2. Actually I removed the axially driven externally regulated
>permanent magnet alternator provided by the engine builder to allow
>reinstalling a harmonic balancer, which he did not feel was
>necessary. The two belt driven 12V, 20 amp permanent magnet
>internally regulated alternators are being provided by me. Seems
>odd that no one has done this, but as a retired electro-mechanical
>engineer, I will work something out when the time comes.
Twin belt driven alternators on an engine
is an exceedingly rare configuration . . . in
fact . . . I'm not aware of anyone having
opted for this arrangement. Doesn't mean it
hasn't happened . . .
If your goal is to achieve 40A of engine
driven capacity, why two separate 20A machines
with no known capability for sharing loads
when driving a common bus? Why not a little
40A ND alternator with a track record?
I've been pondering the twin-stators on the
VW variant. It just may be that the two windings
ARE driven by the same set of magnets, are
the same number of turns and enjoy the same
magnetic efficiency for gathering forces from
the moving magnets for conversion to electron
flow.
If that IS the case, I would think that the
Revmaster installation would recommend parallel
connection of the two windings along with a
suggested rectifier-regulator good for 40A.
Herein lies the uncertainties. THAT much output
from a single phase R-R is hard, every machine of
that power output I'm aware of is a
three phase output with the best R-R designs
going to synchronous field effect rectification
to reduce losses. A legacy R-R design is a rather
inefficient device that begs good thermal management
of dissipated energy. The larger the output,
the more energy dissipated . . . and NOT available
to run your electro-whizzies.
We know that the track record for Ducatti R-R
supplied with Rotax 912/914 engines has a spotty
track-record . . . and that's only an 18A rated
alternator.
There are many, much more robust products
for upgrading the 18A Rotax system. Those
same regulators might be considered for the
dual-coil Revmaster system.
I don't have any way to drive two PM alternators
simultaneously to explore the effectiveness of
PARALLELING two alternator-rectifier-regulators
to the same bus. I'm not saying it WILL NOT work
very nicely . . . I'm just saying I have no practical
way to say, "been there, done than, works good,
lasts a long time".
So you are the pioneering integrator here. When
you run the engine the first time, it would be
useful/interesting to instrument your new,
twin alternator configuration, apply various loads
to the system and see how well they share duties
for grunting a 40A load.
If they parallel to within 10-20% of each other,
odds are that your chosen configuration will
meet your design goals for a 40A, PM system.
The ball is in your court . . .
Bob . . .
Message 3
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Subject: | Engine mount ground? |
I'm running a braided ground from firewall/forest of tabs to engine, is it necessary
to ground the engine mount?
--------
Dave Ford
RV6 for sale
RV10 building
Cadillac, MI
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=452108#452108
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Subject: | Re: Engine mount ground? |
At 12:17 PM 1/19/2016, you wrote:
>
>I'm running a braided ground from firewall/forest of tabs to engine,
>is it necessary to ground the engine mount?
No.
Bob . . .
Message 5
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Subject: | Re: Schematic for twin PM alternators |
I did what I probably should have done at the beginning and made a list of
amperage draw items. The total will allow for the use of one alternator
with the other kept in reserve. So Joe's schematic will work for me. Now
I have to become comfortable with the ramifications.
When the reserve generator is not working due to no power at the IGW
terminal what is happening. Is everything dormant associated with that
generator or is the generator still cranking away creating heat in the
regulator.
How about when the crowbar trips. The IGW is still energized. What
happens to the regulator/generator.
There are two switches that determine which generator is functional. Can
those be combined.
Thanks for all the help
Paul
On Tue, Jan 19, 2016 at 11:02 AM, Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 07:25 AM 1/19/2016, you wrote:
>
> At 10:04 PM 1/18/2016, you wrote:
>
>
> Hi Joe;
> Being internally regulated, each alternator has it's own regulator. I
> think I will probably wire so that only one is in use at a time.
> Cheers!
>
>
> Oops! So the design goals do not include
> simultaneous exploitation of both alternators?
> How do you plan to use this airplane and
> how would the twin alternator installation
> fit into your failure analysis?
>
>
> To: ashleysc@broadstripe.net
> Subject: Re: AeroElectric-List: Re: Schematic for twin PM alternators
>
> At 09:42 PM 1/18/2016, you wrote:
>
> Hi Bob;
> 1. OK. Amounts to the same thing.
> 2. Actually I removed the axially driven externally regulated permanent
> magnet alternator provided by the engine builder to allow reinstalling a
> harmonic balancer, which he did not feel was necessary. The two belt
> driven 12V, 20 amp permanent magnet internally regulated alternators are
> being provided by me. Seems odd that no one has done this, but as a
> retired electro-mechanical engineer, I will work something out when the
> time comes.
>
>
> Twin belt driven alternators on an engine
> is an exceedingly rare configuration . . . in
> fact . . . I'm not aware of anyone having
> opted for this arrangement. Doesn't mean it
> hasn't happened . . .
>
> If your goal is to achieve 40A of engine
> driven capacity, why two separate 20A machines
> with no known capability for sharing loads
> when driving a common bus? Why not a little
> 40A ND alternator with a track record?
>
> I've been pondering the twin-stators on the
> VW variant. It just may be that the two windings
> ARE driven by the same set of magnets, are
> the same number of turns and enjoy the same
> magnetic efficiency for gathering forces from
> the moving magnets for conversion to electron
> flow.
>
> If that IS the case, I would think that the
> Revmaster installation would recommend parallel
> connection of the two windings along with a
> suggested rectifier-regulator good for 40A.
>
> Herein lies the uncertainties. THAT much output
> from a single phase R-R is hard, every machine of
> that power output I'm aware of is a
> three phase output with the best R-R designs
> going to synchronous field effect rectification
> to reduce losses. A legacy R-R design is a rather
> inefficient device that begs good thermal management
> of dissipated energy. The larger the output,
> the more energy dissipated . . . and NOT available
> to run your electro-whizzies.
>
> We know that the track record for Ducatti R-R
> supplied with Rotax 912/914 engines has a spotty
> track-record . . . and that's only an 18A rated
> alternator.
>
> There are many, much more robust products
> for upgrading the 18A Rotax system. Those
> same regulators might be considered for the
> dual-coil Revmaster system.
>
> I don't have any way to drive two PM alternators
> simultaneously to explore the effectiveness of
> PARALLELING two alternator-rectifier-regulators
> to the same bus. I'm not saying it WILL NOT work
> very nicely . . . I'm just saying I have no practical
> way to say, "been there, done than, works good,
> lasts a long time".
>
> So you are the pioneering integrator here. When
> you run the engine the first time, it would be
> useful/interesting to instrument your new,
> twin alternator configuration, apply various loads
> to the system and see how well they share duties
> for grunting a 40A load.
>
> If they parallel to within 10-20% of each other,
> odds are that your chosen configuration will
> meet your design goals for a 40A, PM system.
>
> The ball is in your court . . .
>
>
> Bob . . .
>
Message 6
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Subject: | Re: Engine mount ground? |
The engine mount probably doesn't require a dedicated ground strap as it is
bolted to the firewall and aircraft primary structure.
On Tue, Jan 19, 2016 at 11:17 AM, rvdave <rv610dave@gmail.com> wrote:
>
> I'm running a braided ground from firewall/forest of tabs to engine, is it
> necessary to ground the engine mount?
>
> --------
> Dave Ford
> RV6 for sale
> RV10 building
> Cadillac, MI
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=452108#452108
>
>
Message 7
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Subject: | Re: Engine mount ground? |
It is not necessary to ground the engine mount since it is bolted to the
FW, it is however necessary to ground the engine itself, in many cases the
engine is mounted to the engine mount using rubber mount, these are not
great conductors.....
Nati
On Tue, Jan 19, 2016 at 6:11 PM, John B <jbsoar@gmail.com> wrote:
> The engine mount probably doesn't require a dedicated ground strap as it
> is bolted to the firewall and aircraft primary structure.
>
> On Tue, Jan 19, 2016 at 11:17 AM, rvdave <rv610dave@gmail.com> wrote:
>
>>
>> I'm running a braided ground from firewall/forest of tabs to engine, is
>> it necessary to ground the engine mount?
>>
>> --------
>> Dave Ford
>> RV6 for sale
>> RV10 building
>> Cadillac, MI
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=452108#452108
>>
>>
>>
>>
>>
>>
>>
>> ==========
>> br> fts!)
>> r> > w.buildersbooks.com" rel="noreferrer" target="_blank">
>> www.buildersbooks.com
>> rel="noreferrer" target="_blank">http://www.matronics.com/contribution
>> -Matt Dralle, List Admin.
>> ==========
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>> Electric-List" rel="noreferrer" target="_blank">
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>
Message 8
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Subject: | Re: Schematic for twin PM alternators |
Paul,
I posted two schematics. Which one are you referring to, the first or second?
Here is a link to the second one:
http://forums.matronics.com/download.php?id=42255
My comments below will reference the second one.
The 3 Pole, Single Throw, (3PST) switch is the master switch. It controls the
battery master contactor and also both rectifiers/regulators Ignition terminals.
When the master switch is turned on, the battery contactor is energized and
both regulators are turned on. In case of smoke in the cockpit, I think that
it is a good idea for the master switch to be able to shut off all electrical
power from not only the battery but also from the alternators. The separate
alternator switch selects which one of the two alternators to use, or both off.
I suppose that all switch functions could be combined into one switch at the
risk of putting all eggs into one basket. It is questionable if that one switch
would reduce pilot workload or make the system any more intuitive.
If there is no power going to a regulator Ignition terminal, then that regulator
is shut off. Its dynamo is still generating AC voltage whenever the engine
is running, but no current flows when the regulator disabled and very little heat
is made. Heat goes up with the load on the aircraft electrical system.
If the over-voltage breaker trips or if the selector switch is shut off, then
the alternator relay is de-energized and the alternator power output is shut off.
That situation is no different than if the pilot shuts off each individual electrical
load one device at a time. The dynamo-regulator can not tell the difference
between all individual switches being shut off or one relay shutting everything
off.
The MIA881279 rectifier/regulator is the replacement part number for the John
Deere AM101406 that some have used to replace the Rotax R/R.
Unlike Bob's architecture, my schematic is unproven. So I welcome any comments
or suggestions to prevent steering Paul in the wrong direction.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=452118#452118
Message 9
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Subject: | Re: Engine mount ground? |
Sort of what I thought but I've been getting some feedback that there should also
be a ground cable to the engine mount in case the firewall ground disconnects?
The thinking is that if the one cable disconnects the ground for alternator,
starter may come through braided oil or fuel lines. Is this valid thinking?
--------
Dave Ford
RV6 for sale
RV10 building
Cadillac, MI
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=452119#452119
Message 10
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Subject: | Re: Engine mount ground? |
> On Jan 19, 2016, at 6:34 PM, Nati Niv <n992dn@gmail.com> wrote:
>
> It is not necessary to ground the engine mount since it is bolted to the FW,
it is however necessary to ground the engine itself, in many cases the engine
is mounted to the engine mount using rubber mount, these are not great conductors.....
>
> Nati
Engine mounts should never be used as a ground path. Strap the crankcase to the
ground post. No excuses.
Even though the bolts and bushings that pass thru the rubber components will ohm
out and indicate continuity, carrying electrical loads is not part of their
job description. Many relatively recent aircraft designs incorporate bonding
straps bolted to either side of the vibration isolator and to the crankcase specifically
to keep current out of the mounting points.
Steel is a relatively poor conductor. Joints make it worse by inserting resistance.
High current passed thru a resistive path makes heat, which accelerates
the chemical reaction that we describe as corrosion. Add insidious Galvanic corrosion
due to dissimilar metals in constant contact.
Apart from that, assuming one removes the paint from the mating surfaces, the 4130-steel
engine mount bolted to the stainless or galvanized firewall makes a
poor ground when new and an awful ground as corrosion forms over time.
And it will corrode, despite application of DC 4, Par-al-ketone, ACF-50, (etc.,
pick your favorite goop)...
Neal
Message 11
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Subject: | Re: Engine mount ground? |
Yes, it is valid thinking. You want a good ground, that is mechanically
sound. It goes from the crankcase to the firewall ground. You can include
the engine mount if you wish. Does the engine mount have a convenient
ground tab? If it does, then run another ground strap to your firewall
ground. This won't weigh much, or cost much. (Belt and suspenders, so to
speak.)
Bob Nuckolls writes about this in the manual. A good read!
On Tue, Jan 19, 2016 at 6:22 PM, rvdave <rv610dave@gmail.com> wrote:
>
> Sort of what I thought but I've been getting some feedback that there
> should also be a ground cable to the engine mount in case the firewall
> ground disconnects? The thinking is that if the one cable disconnects the
> ground for alternator, starter may come through braided oil or fuel lines.
> Is this valid thinking?
>
> --------
> Dave Ford
> RV6 for sale
> RV10 building
> Cadillac, MI
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=452119#452119
>
>
Message 12
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Subject: | Carling S700 2-3 switch failure. |
This manual switch is in a high (8 amps?) fast switching injector circuit.
I use it to disable the primary or secondary injectors prior to flight to
determine if the engine will run on only one set of injectors. It failed in
flight and the engine went very lean running on only one set of injectors.
The switch initially had no continuity but made a high resistance contact
after flipping it back and forth a few times.
Should I replace this switch with a more robust one and if so, where would I
find a suitable switch?
Bill
Message 13
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Subject: | Re: Schematic for twin PM alternators |
Hi Bob;
I would parallel them if there is no hazard.=C2- Otherwise I will run the
m separately.=C2- This is a daytime, VFR aircraft, that I hope to take so
me long cross countries in.=C2- It would have two alternators and one bat
tery.=C2- The idea would be not to have to truncate a trip due to one fai
lure.
Cheers!=C2-=C2- Stu.
----- Original Message -----
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Sent: Tuesday, January 19, 2016 5:25:04 AM
Subject: Re: AeroElectric-List: Re: Schematic for twin PM alternators
At 10:04 PM 1/18/2016, you wrote:
Hi Joe;
Being internally regulated, each alternator has it's own regulator.=C2- I
think I will probably wire so that only one is in use at a time.
Cheers!
=C2-=C2- Oops! So the design goals do not include
=C2-=C2- simultaneous exploitation of both alternators?
=C2-=C2- How do you plan to use this airplane and
=C2-=C2- how would the twin alternator installation
=C2-=C2- fit into your failure analysis?
=C2- Bob . . .
Message 14
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Subject: | Re: Carling S700 2-3 switch failure. |
Yes, the switch should be replaced. Choose a switch rated at 10 or more amps.
There are some switches that have the terminals riveted to the plastic housing.
Do NOT use that kind. They depend of the rivets to conduct the current.
Bad idea because rivets in plastic loosen over time. Switches need to be exercised
periodically to wear away corrosion. Switches in airplanes do not get much
exercise and will fail from corrosion before mechanically wearing out. The
S700 2-3 is B & C's part number for a generic DPDT ON-ON switch.
If the load is inductive, a diode connected between the load side of the switch
and ground will protect the switch against arcing. The diode arrow should point
towards positive.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=452125#452125
Message 15
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Subject: | Re: Engine mount ground? |
Yes, it is valid thinking. But it is not necessary or even desired to ground the
engine mount. It will not hurt anything if the engine mount is grounded.
But if a backup ground path is wanted, then run a second ground strap from the
engine block to the firewall.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=452126#452126
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