Today's Message Index:
----------------------
1. 05:23 AM - Re: fused or not (Robert L. Nuckolls, III)
2. 05:35 AM - Re: fused or not (bob noffs)
3. 05:40 AM - Re: Re: fused or not (bob noffs)
4. 06:06 AM - Re: fused or not (user9253)
5. 06:06 AM - Re: Help with Link Trainer (Robert L. Nuckolls, III)
6. 06:41 AM - Re: Re: fused or not (C&K)
7. 07:44 AM - Re: Re: Charging circuit: Sanity check (Carlos Trigo)
8. 09:27 AM - Re: Re: fused or not (bob noffs)
9. 10:46 AM - Re: Charging circuit: Sanity check (user9253)
10. 10:59 AM - Re: Re: fused or not (Robert L. Nuckolls, III)
11. 11:34 AM - Re: fused or not (Robert L. Nuckolls, III)
12. 11:34 AM - Re: Re: Charging circuit: Sanity check (Robert L. Nuckolls, III)
13. 01:34 PM - Re: Charging circuit: Sanity check (Robert L. Nuckolls, III)
14. 02:40 PM - Re: Charging circuit: Sanity check (Charlie England)
15. 03:30 PM - Re: Charging circuit: Sanity check (Robert L. Nuckolls, III)
16. 04:23 PM - Re: Charging circuit: Sanity check (user9253)
17. 05:16 PM - Re: Re: Charging circuit: Sanity check (Robert L. Nuckolls, III)
18. 05:17 PM - Re: Charging circuit: Sanity check (Charles Kuss)
19. 06:35 PM - Re: Charging circuit: Sanity check (Robert L. Nuckolls, III)
20. 07:06 PM - Re: Charging circuit: Sanity check (Charlie England)
21. 07:55 PM - How do I stop audio hash noise generated by a new set of NavStrobes? (DeWitt Whittington)
22. 08:57 PM - Re: How do I stop audio hash noise generated by a new set of NavStrobes? (Daniel Hooper)
23. 10:40 PM - fused or not...now keeping noise out..do caps work? (Bob Verwey)
Message 1
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Subject: | Re: fused or not |
At 07:20 PM 3/26/2016, you wrote:
>i am mounting my capacitor about 3 inches from
>the main bus.i planned on connecting straight to
>the bus main lug with #12 wire and no fuse. should i fuse the cap. for 3''
run?
>=C2 bob noffs
No . . . that wire is not at-risk for
generating any smoke or burning of
other wires. No would a fuse prevent
the very rare condition where the capacitor
goes bad, swells up, smells bad and sometimes
bursts . . . the things should be on your
periodic replacement list . . . say every
5 years or so.
Also consider experiments to see if the
capacitor is necessary/useful. I've not been
able to measure any operational utility beyond
helping us get some PM alternator/rectifiers
to self-excite.
Bob . . .
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Subject: | Re: fused or not |
thanks guys for the info. i am told it is to keep noise out of the ecu.
bob noffs
On Sun, Mar 27, 2016 at 7:20 AM, Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 07:20 PM 3/26/2016, you wrote:
>
> i am mounting my capacitor about 3 inches from the main bus.i planned on
> connecting straight to the bus main lug with #12 wire and no fuse. should
i
> fuse the cap. for 3'' run?
> =C3=82 bob noffs
>
>
> No . . . that wire is not at-risk for
> generating any smoke or burning of
> other wires. No would a fuse prevent
> the very rare condition where the capacitor
> goes bad, swells up, smells bad and sometimes
> bursts . . . the things should be on your
> periodic replacement list . . . say every
> 5 years or so.
>
> Also consider experiments to see if the
> capacitor is necessary/useful. I've not been
> able to measure any operational utility beyond
> helping us get some PM alternator/rectifiers
> to self-excite.
>
>
> Bob . . .
>
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Subject: | Re: fused or not |
i guess i don't really know how much a cap. pulls initially. i am sure
somewhere i saw a schematic using 12 ga. if this is overkill what is
recommended for a 10000uf?
bob
On Sat, Mar 26, 2016 at 9:59 PM, user9253 <fransew@gmail.com> wrote:
>
> 12awg seems way too big.
> There is not much danger for a 3" wire shorting out. But capacitors have
> been known to short, not likely but possible.
>
> --------
> Joe Gores
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=454201#454201
>
>
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Subject: | Re: fused or not |
I do know what wire size to use for a 10000uf capacitor. But a capacitor only
draws lots of current when it is first energized. And that is for such a short
time (less than a second) that the wire does not even begin to warm up. A wild
guess would be to use 18 awg. Maybe someone more knowledgeable will answer.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=454211#454211
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Subject: | Re: Help with Link Trainer |
>[]
>
Larry, thanks for the picture. That is NOT
a d-sub connector. That series of connectors
started life in avionics back in the 60s as
"Winchester" connectors and eventually picked
up by AMP. Originally solder-only they morphed
into their "M" series connectors with removable
crimp pins.
See http://tinyurl.com/hu5wdpj
Those use the Series II pins and I think the
extraction too looks like this
[]
http://media.digikey.com/photos/Tyco%20Amp%20Photos/305183.jpg
I need to do some more catalog surfing to make
sure we get you the right parts but I've got a
living room full of grandkids who are going to
want to search for Easter eggs when they wake
up . . . this year's hunt will have to be inside
I think . . . it SNOWED last night.
Refresh my memory, do you need to replace one or
more of these connectors or just de-pin them
for re-installation?
Bob . . .
Message 6
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Subject: | Re: fused or not |
FWIW I agree if there is no battery in the circuit.
If there is a battery then my advice would be to forget the capacitor.
I've run for many years without a capacitor with a 20 amp PM alternator
and a small battery. I've run many different ecu based electronic
devices (homemade and commercial) without a problem and without any
evidence that a capacitor would add any value. Even running my ignition
off that system makes no practical difference. Who needs extra parts and
extra maintenance issues. Lots of urban legend involved with the use of
this large capacitor from what I can tell. I'm not saying the battery
replaces the capacitor, I'm just saying that I've no experience running
without a battery.
Ken
On 27/03/2016 9:05 AM, user9253 wrote:
>
> I do know what wire size to use for a 10000uf capacitor. But a capacitor only
draws lots of current when it is first energized. And that is for such a short
time (less than a second) that the wire does not even begin to warm up. A
wild guess would be to use 18 awg. Maybe someone more knowledgeable will answer.
>
> --------
> Joe Gores
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=454211#454211
>
>
Message 7
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Subject: | Re: Charging circuit: Sanity check |
Charlie
I didn't get your revised drawing.
Will you please re-post it?
Thanks
Carlos
Enviado do meu iPhone
No dia 26/03/2016, =C3-s 16:53, Charlie England <ceengland7@gmail.com> esc
reveu:
> Thanks, Joe; responses inserted below.
>
>> On Sat, Mar 26, 2016 at 11:48 AM, user9253 <fransew@gmail.com> wrote:
>>
>> If both alternators are online at the same time,
>> over voltage on one alternator could cause both
>> over-voltage modules to short and trip their breakers.
> You're right, of course. Looks like the only option would be to diode isol
ate the alts outputs from each other, and do OV detection behind the diodes.
Unfortunately, that induces up to .45V drop, even with Schottky diodes. Mig
ht be able to get away with that & still charge the battery properly; might n
ot. Would be nice to be able to adjust an internally regulated alternator's o
utput...
>>
>> Considering that many modern avionics can operate
>> between 12 and 30 volts, automatic over-voltage
>> protection might not be necessary. The battery might
>> resist voltage rise for a minute until the pilot reacts to
>> the EFIS high voltage warning and shuts off the alternator.
> True, but I'd prefer not to depend on my reaction time if the event comes d
uring at high workload time. Will keep that option in mind.
>>
>> There is no automatic switch over to alternator 2 because
>> that bottom relay will never drop out while the main bus
>> is hot unless alternator 1 breaker is pulled or tripped.
> Correct. I've been focused entirely on OV events, and neglected the *under
*voltage possibility. Perhaps I can live with that; with undervoltage alerts
from the EFIS and battery capacity, I should have a longer safe response wi
ndow.
>>
>> The bottom relay will have to be able to handle full main-
>> switch #2 current because very little will flow through
>> the diode. The relay contacts short out the diode.
> Correct, and I noticed that as I was typing the 1st email. I think I menti
oned an omitted 2nd diode.
> I've attached a revised drawing with the additional diode, and the NC rela
y in the correct position. I also added a fuse link to the feed line for th
e auto-transfer supply, for wire protection. Consider the auto-transfer comp
onents below the 'hash' line as optional, but desirable to me.
>
> As drawn, I should be able to pull alt1's CB, close alt2's main supply swi
tch, and start the engine. (Start control not included in the drawing.) Afte
r engine start, verify 14V from alt2, then close alt1's main supply switch, o
pen alt2's supply switch, and close alt1's CB. Then verify 14V from alt1.
>
> As mentioned in a previous email, I'm not crazy about resetting the CB eve
ry flight, but CB specs seem to indicate ~2500 cycle life for pullable CBs, s
o it might get the same treatment as Bob's 'battery rotation' concept and be
replaced at every 4th or 5th annual. (Even that would be overkill for me; I
don't fly that often.)
>
> An OV fault should bring alt2 online automatically, and I'll add detection
to the auto-transfer relay to get notification if it activates alt2.
> I'll depend on the EFIS for under-voltage notification and bring alt2 onli
ne manually by pulling alt1's CB (would also remove any potential load cause
d by the defective alt1).
>
> Still not locked-in to using the 50A switches, but am still leaning that w
ay. Should have drawn the fuse links in this revision, but forgot. Won't for
get to install them, though. :-)
>
> Thanks again, Joe. Any more thoughts, anyone?
>
> Charlie
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Subject: | Re: fused or not |
well........one failure mode of an engine with elec pumps etc. is
alternator power only. whether or not i ever need the cap. is another issue
but it was recommended i use one. this is for the honda/viking 110
installation.
bob
On Sun, Mar 27, 2016 at 8:39 AM, C&K <yellowduckduo@gmail.com> wrote:
>
> FWIW I agree if there is no battery in the circuit.
>
> If there is a battery then my advice would be to forget the capacitor.
> I've run for many years without a capacitor with a 20 amp PM alternator
> and a small battery. I've run many different ecu based electronic devices
> (homemade and commercial) without a problem and without any evidence that a
> capacitor would add any value. Even running my ignition off that system
> makes no practical difference. Who needs extra parts and extra maintenance
> issues. Lots of urban legend involved with the use of this large capacitor
> from what I can tell. I'm not saying the battery replaces the capacitor,
> I'm just saying that I've no experience running without a battery.
>
> Ken
>
>
> On 27/03/2016 9:05 AM, user9253 wrote:
>
>>
>> I do know what wire size to use for a 10000uf capacitor. But a capacitor
>> only draws lots of current when it is first energized. And that is for
>> such a short time (less than a second) that the wire does not even begin to
>> warm up. A wild guess would be to use 18 awg. Maybe someone more
>> knowledgeable will answer.
>>
>> --------
>> Joe Gores
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=454211#454211
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
Message 9
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Subject: | Re: Charging circuit: Sanity check |
Here is a schematic for you Charlie
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=454223#454223
Attachments:
http://forums.matronics.com//files/charlie_457.pdf
http://forums.matronics.com//files/charlie_142.jpg
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Subject: | Re: fused or not |
At 08:05 AM 3/27/2016, you wrote:
>
>I do know what wire size to use for a 10000uf capacitor. But a
>capacitor only draws lots of current when it is first
>energized. And that is for such a short time (less than a second)
>that the wire does not even begin to warm up. A wild guess would be
>to use 18 awg. Maybe someone more knowledgeable will answer.
that short of run would be fine with 22AWG
but most of the TC world uses 20AWG minimum
under the cowl just for mechanical robustness.
Bob . . .
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Subject: | Re: fused or not |
At 07:33 AM 3/27/2016, you wrote:
>thanks guys for the info. i am told it is to keep noise out of the ecu.
>=C2 bob noffs
That IS the legacy rationale for adding such things
and it's a deeply rooted idea did
a failure analysis on a modern, 100A alternator
that came equipped from the factory with a 680uF
electrolytic capacitor mounted right to the back
of the alternator.
Emacs!
I am quite certain that noise from this alternator on
EMC laboratory equipment would not be materially
reduced for having added the capacitor. I'd
LOVE to see an EMC test report that illuminates
the 'benefit'.
I just purchased a spectrum analyzer that sweeps
down to 1Hz and up to 2.4 Ghz. When I begin
development testing on the next generation of
PM alternator rectifier/regulators for B&C I will
quantify the value of adding this component
to our airplanes.
Bob . . .
Message 12
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Subject: | Re: Charging circuit: Sanity check |
If both alternators are online at the same time,
over voltage on one alternator could cause both
over-voltage modules to short and trip their breakers.
The B&C LR/LS series regulators are fitted with
circuits to identify WHICH of two regulators is
causing the OV condition. If a regulator is working
right, the OV condition drives the field output votlage
to zero . . . and OV trip for THAT regulator is inhibited.
Hence, only the regulator with a runaway field output
is allowed to exercise its circuit breaker.
Considering that many modern avionics can operate
between 12 and 30 volts, automatic over-voltage
protection might not be necessary.=C2 The battery might
resist voltage rise for a minute until the pilot reacts to
the EFIS high voltage warning and shuts off the alternator.
We'd never be allowed to field such a system in TC
aircraft. Given that it's so easy to deal with
the dual alternator situation, there's no reason
to loose much sleep over it.
If you've installed two, bare-footed crowbar
ov modules, then yes, you'd get a dual trip if
both alternators are ON . . . then turn them
back on one at a time . . . no big deal. If
one alternator is a stand-by and OFF for normal
ops, then only the operating alternator's ov
protection would operate making diagnostics
simpler yet.
As drawn, I should be able to pull alt1's CB,
close alt2's main supply switch, and start the
engine. (Start control not included in the
drawing.) After engine start, verify 14V from
alt2, then close alt1's main supply switch, open
alt2's supply switch, and close alt1's CB. Then verify 14V from alt1.
Anytime somebody uses the word 'automatically', my
little red head-flags go up. One should first
identify the risk for allowing some otherwise
automated condition to proceed while awaiting
pilot notice and action.
For example, suppose you had two, independently
controlled alternators driving the same bus
structure with one alternator held in reserve
by keeping it's field supply open.
When the first alternator craps, you get a low
voltage warning light . . . if you've done due
diligence with respect to your battery, you can
finish your coffee, fold and stow a map and
then bring the standby alternator on line
while taxing your stored battery energy to perhaps
1% of total.
In other words, what is the value of adding lots
the bells, whistles, diodes, relays, etc. etc?
System MTBF is inversely proportional to parts
count . . . a part that is NOT installed will
NOT be the part that caused you to drag
out a toolbox.
Do your FMEA study guys . . . and evaluate risk
to comfortable completion of flight before you
complicate the system.
As a general rule, there is little or no value
added to OBAM aircraft systems for having incorporated
'automatic' features so popular with the purveyors
of push-button systems over the counters at OSH.
Bob . . .
Message 13
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Subject: | Re: Charging circuit: Sanity check |
At 05:27 PM 3/25/2016, you wrote:
>Greetings,
>
>I need a sanity check on my current thoughts for
>the charging circuit in my RV-7.
>
>Please note that this is *not* a typical Lyc
>installation, so many of the assumed requirements/limits do not apply.=C2
>
>Engine: Mazda Renesis automotive conversion with total electrical
dependency.
>
>Alternator(s): 2 ea identical ND internally
>regulated alternators, each rated at 60 amps.
>(This choice was driven by both budget
>constraints and simplicity of installation)
>
>My goals/choices are:
>1. 'Unlimited' availability of electrical power,
>to avoid in-route diversion in the case of
>alternator failure. I accept a single
>battery,due to the very small likelihood of
>battery failure. Fuel will easily outlast any
>but very big/heavy batteries. A PC680 is good
>for only ~45 minutes with only the engine
>consuming electrons; much less time with avionics on line.
>
>2.Redundant paths of power to the buss, due to
>the engine's total dependence on electricity.=C2
>
>3. Ability to check both alternators for proper operation before flight.
Take a peek at this drawing
http://tinyurl.com/zpww8ag
and see if it doesn't do what you want.
All engine stuff runs off battery bus. E-bus has dual
feeds one of which mitigates loss of battery contactor.
S/B alternator feeds battery directly which also
goes to mitigating loss of battery contactor. Simple
controls with no hazard to system for having more than
one alternator active.
Bob . . .
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Subject: | Re: Charging circuit: Sanity check |
On 3/27/2016 3:30 PM, Robert L. Nuckolls, III wrote:
> At 05:27 PM 3/25/2016, you wrote:
>> Greetings,
>>
>> I need a sanity check on my current thoughts for the charging circuit
>> in my RV-7.
>>
>> Please note that this is *not* a typical Lyc installation, so many of
>> the assumed requirements/limits do not apply.
>>
>> Engine: Mazda Renesis automotive conversion with total electrical
>> dependency.
>>
>> Alternator(s): 2 ea identical ND internally regulated alternators,
>> each rated at 60 amps.
>> (This choice was driven by both budget constraints and simplicity of
>> installation)
>>
>> My goals/choices are:
>> 1. 'Unlimited' availability of electrical power, to avoid in-route
>> diversion in the case of alternator failure. I accept a single
>> battery,due to the very small likelihood of battery failure. Fuel
>> will easily outlast any but very big/heavy batteries. A PC680 is good
>> for only ~45 minutes with only the engine consuming electrons; much
>> less time with avionics on line.
>>
>> 2.Redundant paths of power to the buss, due to the engine's total
>> dependence on electricity.
>>
>> 3. Ability to check both alternators for proper operation before flight.
>
> Take a peek at this drawing
>
> http://tinyurl.com/zpww8ag
>
> <http://tinyurl.com/zpww8ag> and see if it doesn't do what you want.
>
> All engine stuff runs off battery bus. E-bus has dual
> feeds one of which mitigates loss of battery contactor.
> S/B alternator feeds battery directly which also
> goes to mitigating loss of battery contactor. Simple
> controls with no hazard to system for having more than
> one alternator active.
>
>
> Bob . . .
>
Looks good, but do I need multiple busses, when I'll be running 2
identical alternators? The auto conversion engine has the advantage that
I'm not restricted to a vacuum pad mount for the 2nd alt, like a Lyc
would be. So the entire aircraft's electrical loads can be supported by
either alternator.
I'd prefer internally regulated alternators, as well. I've followed
others' issues with them in the past, but I've used them on my RV-4's
for years and I'm comfortable with them. I won't be 'load dumping'
unless the alternator has already failed. My only real concern would be
pre-flight testing of both alternators. My hope would be engine start
with only the backup alternator on line, check for proper operation,
then take the backup off line (while operating at low power) and bring
the primary on line to verify its operation.
Do you see any issues with this?
Thanks,
Charlie
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Subject: | Re: Charging circuit: Sanity check |
Looks good, but do I need multiple busses, when I'll be running 2
identical alternators?
Not sure what you mean . . . eliminate the e-bus? Sure, you can do
that.
The auto conversion engine has the advantage that I'm not restricted
to a vacuum pad mount for the 2nd alt, like a Lyc would be. So the
entire aircraft's electrical loads can be supported by either alternator.
Understand. The drawing as submitted supports that
requirement.
I'd prefer internally regulated alternators, as well. I've followed
others' issues with them in the past, but I've used them on my RV-4's
for years and I'm comfortable with them. I won't be 'load dumping'
unless the alternator has already failed.
That's what I have illustrated . . .
Load dumping damage is a will-o-the-whisp that arose
from the smoke with alternators popular in the
RV crowd many years ago. I think those were
some product offered by Van's. Read the chapter
on alternators for a description of how ANY alternator
remanufactured by ANY reputable shop demonstrates
MULTIPLE max rpm, max load, max temperature load
dumps.
My only real concern would be pre-flight testing of both alternators.
You can do that. In fact, the airplane can be
routinely flown on either alternator.
My hope would be engine start with only the backup alternator on line, check
for proper operation, then take the backup off line (while operating
at low power)
and bring the primary on line to verify its operation.
That or any other combination of switch-flips are
equally valid . . .
I've revised the drawing to eliminate the e-bus.
You still want to connect the s/b alternator directly
to the battery so that shutting down the DC PWR MASTER
gets the electrical system max-cold . . . for smoke
in the cockpit events. See http://tinyurl.com/zm46jzm
Bob . . .
Message 16
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Subject: | Re: Charging circuit: Sanity check |
One bus is OK, but consider:
Is it possible for that bus to lose power?
If it does lose power, what are the symptoms?
If loads critical to flight safety get power from
that bus, what is the backup plan?
Having two alternators does not necessarily mean that the
main power bus will not lose power. It all depends on how
the aircraft is wired.
The ignition and fuel pump of an electrically dependent
engine should be powered directly from the battery.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=454238#454238
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Subject: | Re: Charging circuit: Sanity check |
At 06:21 PM 3/27/2016, you wrote:
>
>One bus is OK, but consider:
>Is it possible for that bus to lose power?
>If it does lose power, what are the symptoms?
>If loads critical to flight safety get power from
>that bus, what is the backup plan?
>Having two alternators does not necessarily mean that the
>main power bus will not lose power. It all depends on how
>the aircraft is wired.
>The ignition and fuel pump of an electrically dependent
>engine should be powered directly from the battery.
As a general rule, the reliability of a
well crafted bus structure is as robust
as prop-bolts. The reason for multiple busses
in the z-figures speaks efficient utilization
of a limited resource . . . in the case of Z-11,
batty only flight. In the case of Z-13/8, limits
of output on an 8A PM alternator. In the case
of electrically dependent engines, running all
the engine stuff from the battery bus keeps
the fan blowing with all other electrical system
shut down.
Z-12 is illustrative of bus structure on thousands
of TC aircraft flying an SD-20 s/b alternator. One
battery, two alternators, one bus . . . oh yeah,
they DO have an avionics bus but those don't count . . .
they serve no practical or necessary energy
management purpose.
In no instance was a bus added to 'back up' another
bus. It's existence facilitates partitioning energy
delivery onto narrowly defined tasks under specific
circumstances.
Bob . . .
Message 18
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Subject: | Re: Charging circuit: Sanity check |
snipped
The auto conversion engine has the advantage that I'm not restricted to a vacuum
pad mount for the 2nd alt, like a Lyc would be. So the entire aircraft's
electrical loads can be supported by either alternator.
snipped
Are both these alternators going to be belt driven? If so, when one belt breaks,
it often fouls the belt for the second alternator and causes it to jump off
it's pulleys. Thus, a single belt failure can disable BOTH alternators. Bob's
been designing this stuff for over 30 years. How much time/thought did you put
into your design? In a failure of all the power generating sources [alternators/dynamos/generators]
it would behoove you to have an essential bus, to rapidly
shed unneeded power. Also consider a smaller, secondary battery, to power this
bus.
Charlie
Message 19
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Subject: | Re: Charging circuit: Sanity check |
>
>Are both these alternators going to be belt driven? If so, when one
>belt breaks, it often fouls the belt for the second alternator and
>causes it to jump off it's pulleys. Thus, a single belt failure can
>disable BOTH alternators.
Excellent question . . . if this is a high-risk
event irrespective of probability, then replacing
the belt every 100 hrs or so seems prudent. Also,
use Gates belts if you can get 'em . . .
Plan B might include a detailed load analysis after
having shed all non-essential loads while maintaining
battery capacity at useful endurance levels.
Bob . . .
Message 20
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Subject: | Re: Charging circuit: Sanity check |
CgotLS0tLS0tLSBPcmlnaW5hbCBtZXNzYWdlIC0tLS0tLS0tCkZyb206ICJSb2JlcnQgTC4gTnVj
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Z2luZyBldmVuIGRpcmVjdCBkcml2ZS4gCgpDaGFybGll
Message 21
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Subject: | How do I stop audio hash noise generated by a new set |
of NavStrobes?
Hello, Bob, and all you AeroElectric forum participants. This is the first time
Ive posted in years, but Ive got a problem I cant solve. At Oshkosh 2015 I bought
a set of the NavStrob LED nav/position light units. They directly replace
the red and green wingtip nave bulbs, and the white rear position light. I cleaned
out the sockets for all three locations and sprayed them with CorrosionX.
Then inserted the NavStrobe units. When you turn on the Nav light switch once,
all three burn with a steady light. Flip them off, and turn on again, and they
flash like strobes. Slick. But, in my 1975 172L, when we turn on the COM radios,
then turn on the strobes, there is a very unpleasant hash noise when the
VOX gate opens as when you speak or a transmission comes in from someone else.
The designer of the NavStrobe unit suggests cleaning all the light sockets again.
And if that doesnt get rid of the hash noise (and it didnt) install a choke
coil.
So, any suggestions? And what size or type of choke should I buy and where do I
install it? All suggestions welcome.
Dee Whittington
Message 22
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Subject: | Re: How do I stop audio hash noise generated by a new |
set of NavStrobes?
It could possibly be ground noise. What is the wiring configuration for your nav
lights and intercom?
--Daniel
> On Mar 27, 2016, at 9:52 PM, DeWitt Whittington <dee.whittington@gmail.com> wrote:
>
>
> Hello, Bob, and all you AeroElectric forum participants. This is the first time
Ive posted in years, but Ive got a problem I cant solve. At Oshkosh 2015 I
bought a set of the NavStrob LED nav/position light units. They directly replace
the red and green wingtip nave bulbs, and the white rear position light. I
cleaned out the sockets for all three locations and sprayed them with CorrosionX.
Then inserted the NavStrobe units. When you turn on the Nav light switch once,
all three burn with a steady light. Flip them off, and turn on again, and
they flash like strobes. Slick. But, in my 1975 172L, when we turn on the COM
radios, then turn on the strobes, there is a very unpleasant hash noise when
the VOX gate opens as when you speak or a transmission comes in from someone else.
>
> The designer of the NavStrobe unit suggests cleaning all the light sockets again.
And if that doesnt get rid of the hash noise (and it didnt) install a choke
coil.
>
> So, any suggestions? And what size or type of choke should I buy and where do
I install it? All suggestions welcome.
>
> Dee Whittington
>
>
>
>
>
>
>
Message 23
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Subject: | fused or not...now keeping noise out..do caps work? |
Bob,
In the same vein...
After having a new intercom fitted in my radio stack, I have developed a
serious amount of radio noise as soon as the rpm's hit the 2000 mark. The
sq button has no effect on the severity of this noise. It is as if a source
is transmitting to the radio!
I am told that adding a 22000 microfarad cap across the power feed to the
radios will solve this problem.
What says the brains trust?
On 27 March 2016 at 19:39, Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 07:33 AM 3/27/2016, you wrote:
>
> thanks guys for the info. i am told it is to keep noise out of the ecu.
> =C3=82 bob noffs
>
>
> That IS the legacy rationale for adding such things
> and it's a deeply rooted idea did
> a failure analysis on a modern, 100A alternator
> that came equipped from the factory with a 680uF
> electrolytic capacitor mounted right to the back
> of the alternator.
>
>
> [image: Emacs!]
>
> I am quite certain that noise from this alternator on
> EMC laboratory equipment would not be materially
> reduced for having added the capacitor. I'd
> LOVE to see an EMC test report that illuminates
> the 'benefit'.
>
> I just purchased a spectrum analyzer that sweeps
> down to 1Hz and up to 2.4 Ghz. When I begin
> development testing on the next generation of
> PM alternator rectifier/regulators for B&C I will
> quantify the value of adding this component
> to our airplanes.
>
>
> Bob . . .
>
--
Best...
Bob Verwey
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