Today's Message Index:
----------------------
1. 06:37 AM - Voltage Runaway on Plane Power Alternator (Richard Talbot)
2. 07:17 AM - Re: KY 196 pinouts (Robert L. Nuckolls, III)
3. 07:17 AM - Re: Voltage Runaway on Plane Power Alternator (Robert L. Nuckolls, III)
4. 07:34 AM - Re: Radio Noise Problems - Rotax 914 Alternator Problems (user9253)
5. 08:15 AM - Re: Voltage Runaway on Plane Power Alternator (Hinde, Frank George (Corvallis))
6. 08:37 AM - Re: LR3 regulator Amperage indications (Bill Schertz)
7. 09:10 AM - Re: Radio Noise Problems - Rotax 914 Alternator Problems (darinh)
8. 11:59 AM - Re: Re: Radio Noise Problems - Rotax 914 Alternator Problems (David E. Nelson)
9. 01:33 PM - Re: LR3 regulator Amperage indications (Robert L. Nuckolls, III)
10. 01:56 PM - Re: Re: Radio Noise Problems - Rotax 914 Alternator Problems (Robert L. Nuckolls, III)
11. 03:41 PM - Re: Radio Noise Problems - Rotax 914 Alternator Problems (user9253)
12. 06:07 PM - Re: Tunnel grounding (woxofswa)
13. 08:36 PM - Arinc 429 source to 429 receivers (Kevin Carey)
14. 10:03 PM - Re: Re: Tunnel grounding (Robert L. Nuckolls, III)
15. 10:03 PM - Re: Arinc 429 source to 429 receivers (Robert L. Nuckolls, III)
Message 1
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| Subject: | Voltage Runaway on Plane Power Alternator |
G'day Everyone,
I have a strange fault that has developed on my RV7, with Plane Power Inter
nally regulated alternator. I bought is as it has crowbar voltage protecti
on built in. The aircraft has 20 hours on it and up till recently the alte
rnator worked fine.
The last two flights I have received Over Voltage alerts on takeoff from my
EFIS and the 5A breaker has popped - so I guess the crowbar works as adver
tised and my avionics is all OK. Resetting the breaker works fine once at
pattern altitude and the prop is back to 2500 RPM or so. The unit then per
forms flawlessly for the rest of the flight. I have not tried applying tak
eoff power at altitude, so I cannot be certain it is the high RPM causing i
t.
I called the guys at Plane Power and they suggested checking the field line
and breaker which I will do tomorrow. However, this is a pretty strange f
ailure mode and I was wondering if anyone else on the list had any ideas.
I don't really want to risk cooking my radios etc. There really is not muc
h that can go wrong with the unit's wiring as it only has two wires connect
ed to it.
Thanks/Regards
Richard
Sydney, Australia
Message 2
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| Subject: | Re: KY 196 pinouts |
At 11:15 PM 5/7/2009, you wrote:
>
>Does anyone have the pinouts for the edge connector on a KY
>196? Looking to try and wire it up.
>
>Thanks
>Doug
http://www.aeroelectric.com/Installation_Data/KY196_197_Series.pdf
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 3
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| Subject: | Re: Voltage Runaway on Plane Power Alternator |
At 08:35 AM 5/8/2009, you wrote:
>G'day Everyone,
>
>I have a strange fault that has developed on my RV7, with Plane
>Power Internally regulated alternator. I bought is as it has
>crowbar voltage protection built in. The aircraft has 20 hours on
>it and up till recently the alternator worked fine.
>
>The last two flights I have received Over Voltage alerts on takeoff
>from my EFIS and the 5A breaker has popped - so I guess the crowbar
>works as advertised and my avionics is all OK. Resetting the
>breaker works fine once at pattern altitude and the prop is back to
>2500 RPM or so. The unit then performs flawlessly for the rest of
>the flight. I have not tried applying takeoff power at altitude, so
>I cannot be certain it is the high RPM causing it.
>
>I called the guys at Plane Power and they suggested checking the
>field line and breaker which I will do tomorrow. However, this is a
>pretty strange failure mode and I was wondering if anyone else on
>the list had any ideas. I don't really want to risk cooking my
>radios etc. There really is not much that can go wrong with the
>unit's wiring as it only has two wires connected to it.
There is only one reason for an alternator to produce
TOO MUCH voltage . . . serious fault in the regulator's
ability to sense bus voltage -OR- some failure within
the regulator's itty-bitty innards.
It's unusual for an electronic failure on an integrated
circuit to be intermittent/transient as you've described.
But as you've observed, the ov protection system is ringing
loud bells to let you know that the system needs some
attention to details. It's unfortunate that you're so
remote to the Plain Power facilities. If I were Plane
Power, I'd want to get the unit back for inspection.
I think it unlikely that "loose wiring" in the airplane
would cause this, more likely that the problem is internal
to the alternator. Work closely with Plane Power. They
know more about their product than anybody else.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 4
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| Subject: | Re: Radio Noise Problems - Rotax 914 Alternator Problems |
Darin,
It sounds like the rectifier/regulator is at fault. Depending on the cost, the
easy way to trouble shoot is to replace it and see if that fixes the problem.
If you know someone with an oscilloscope, looking at the waveform will tell
if the rectifier/regulator is doing its job. A diode or its connections could
be open. Instead of outputting steady DC, the output could be pulsing DC. Lacking
an oscilloscope, measure the output with a voltmeter set to AC. Compare
the voltage readings of each alternator with the meter set to DC and also set
to AC. Let us know what you find.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=243138#243138
Message 5
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| Subject: | Voltage Runaway on Plane Power Alternator |
Yes should be easy to check that you have the right field connections (make sure
you cheeck of good crimps or soldered joints between the wires and the terminals
connected to the alt..More than once I have pulled a wire clean out of a
ring terminal bolted to the B post.
Make sure you have a good ground between the engine and -ve terminal to the battery...I
assume your using the Plane power Cad plated brackets?...Because if you
using painted brackets this can interrupt the ground between the alt case and
the engine block..Ask me how I know...:)
But I agree with Bob, if you can't find a wiring fault I'd send it back to plane
power.
Frank
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III
Sent: Friday, May 08, 2009 7:15 AM
Subject: Re: AeroElectric-List: Voltage Runaway on Plane Power Alternator
--> <nuckolls.bob@aeroelectric.com>
At 08:35 AM 5/8/2009, you wrote:
>G'day Everyone,
>
>I have a strange fault that has developed on my RV7, with Plane Power
>Internally regulated alternator. I bought is as it has crowbar voltage
>protection built in. The aircraft has 20 hours on it and up till
>recently the alternator worked fine.
>
Message 6
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| Subject: | Re: LR3 regulator Amperage indications |
Bob,
The heavy B lead comes off the B&C alternator, and passes through a sensor
supplied by Blue Mountain avionics, which I believe is a Hall effect
transducer, and then goes to the Batteries. The Voltage is measured at the
Main buss.
I am enclosing the output from the last flight showing the variations.
Bill Schertz
KIS Cruiser #4045
N343BS
Phase I testing
----- Original Message -----
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
>
> Where are you measuring current and voltage? The LR series
> regulators are linear devices i.e. smoothly variable DC output
> voltage. But without knowing exactly where you are sampling
> voltage and current, I'm unable to deduce the significance
> of your observations.
>
>
> Bob . . .
>
> ----------------------------------------)
> ( . . . a long habit of not thinking )
> ( a thing wrong, gives it a superficial )
> ( appearance of being right . . . )
> ( )
> ( -Thomas Paine 1776- )
> ----------------------------------------
>
>
>
Message 7
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| Subject: | Re: Radio Noise Problems - Rotax 914 Alternator Problems |
Joe,
Thanks for the reply. I don't have access to an oscilloscope but can measure voltage
using a meter on AC. What in particular would I be looking for when comparing
the AC vs. DC? I would expect to see around 14.0vdc but what am I looking
for with AC? Maybe a dumb question but I am dumb when it comes to this stuff.
--------
Darin Hawkes
Series 7
914 Turbo
Kaysville, Utah
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=243151#243151
Message 8
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| Subject: | Re: Radio Noise Problems - Rotax 914 Alternator |
Problems
Hi Darin,
While an o-scope would be preferable, many years ago I was told that I could use
a Volt-Ohm-Meter to do a quick check of a diode bridge for a running alternator
by measuring the AC voltage. I've never had the opportunity (knock on wood) to
verify this, however.
I think our basic alternator is essentially a 3 phase alternator. So if a diode
fails, I'd think the number would be in neighborhood of 12V/3phase = 4 VAC/phase
(there may be a small multiplier in there somewhere) rather in the sub 1 VAC
(ripple voltage).
I'm sure the Bob will chime in here somewhere and either validate or correct.
Either way, I'd like to update my notes.
Regards,
/\/elson
~~ Lately my memory seems to be like a steel trap .... without any spring. ~~
On Fri, 8 May 2009, darinh wrote:
>
> Joe,
>
> Thanks for the reply. I don't have access to an oscilloscope but can measure
> voltage using a meter on AC. What in particular would I be looking for when
> comparing the AC vs. DC? I would expect to see around 14.0vdc but what am I
> looking for with AC? Maybe a dumb question but I am dumb when it comes to
> this stuff.
>
> --------
> Darin Hawkes
> Series 7
> 914 Turbo
> Kaysville, Utah
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=243151#243151
>
>
Message 9
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| Subject: | Re: LR3 regulator Amperage indications |
At 10:33 AM 5/8/2009, you wrote:
>Bob,
>The heavy B lead comes off the B&C alternator, and passes through a
>sensor supplied by Blue Mountain avionics, which I believe is a Hall
>effect transducer, and then goes to the Batteries. The Voltage is
>measured at the Main buss.
>
>I am enclosing the output from the last flight showing the variations.
Those traces are almost certainly plagued with data sampling
artifacts polluted by noise. There's no way that the "real"
numbers are that trashy. Have you explored the R/C filtering
I suggested? How many bits of resolution does the data
acquisition system offer?
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 10
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| Subject: | Re: Radio Noise Problems - Rotax 914 Alternator |
Problems
At 01:55 PM 5/8/2009, you wrote:
><david.nelson@pobox.com>
>
>
>Hi Darin,
>
>While an o-scope would be preferable, many years ago I was told that
>I could use a Volt-Ohm-Meter to do a quick check of a diode bridge
>for a running alternator by measuring the AC voltage. I've never
>had the opportunity (knock on wood) to verify this, however.
>
>I think our basic alternator is essentially a 3 phase
>alternator. So if a diode fails, I'd think the number would be in
>neighborhood of 12V/3phase = 4 VAC/phase (there may be a small
>multiplier in there somewhere) rather in the sub 1 VAC (ripple voltage).
>
>I'm sure the Bob will chime in here somewhere and either validate or
>correct. Either way, I'd like to update my notes.
The rectified DC output from a 3-phase alternator
carries about 5% pk-pk ripple. In a 14v system
this is about 0.7 volts. Problem is that there's
a lot of diode switching noise that can be higher.
Depending on the design of the voltmeter, the AC
readings can be all over the place.
At Electro-Mech about 25 years ago, I looked at
offering an accessory to the aircraft industry
based on ac ripple monitoring. There were a number
of ideas/products in the wild that purported
to do the same thing. One example:
http://tinyurl.com/oummzc
What I discovered was that the "smarts" necessary
to accurately detect diode failure under all
operating conditions and all variations on a theme
for alternators in the field made for a pretty
expensive device . . . that didn't really do much
more than a low-voltage warning light. The claims
offered in the patent cited above cannot be supported
in broad practice.
Having said that, if you have a BENCHMARK ac ripple
voltage measurement with a specific instrument,
you can use that combination to tell that something
has drastically changed . . .
The last time I looked at a Rotax 912, it was still
a single phase machine . . . MUCH higher ripple
voltage that is drastically altered how hard the
rectifier/regulator is taxing the alternator. AC
rippled measurements at the DC side might be
a useful diagnostic tool IF you had benchmark
measurements to compare with . . . but unless you
know what the GOOD measurements look like, it's
not likely that you can identify a BAD measurement.
I gave up the AC ripple monitor in favor of the
rudimentary LV warning light. We sold several versions
to about a half dozen airframe OEM.
Bob . . .
Message 11
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| Subject: | Re: Radio Noise Problems - Rotax 914 Alternator Problems |
> What in particular would I be looking for when comparing the AC vs. DC?
Darin,
I probably gave you bad advice to check the AC output of the alternator because
many meters will not give an accurate reading. I used a Fluke 76 meter (which
I trust) and measured 0.015 volts AC at the battery on my Ford Expedition with
the engine running. However, when I used a couple of other meters, they read
anywhere between 12 and 30 volts. Bob Nuckolls book tells how to test an alternator
while bypassing the regulator. Other than replacing the rectifier/regulator,
the only thing that I can suggest is to test the diodes with an ohmmeter,
if they are accessible. Double check all wires and connections. The majority
of electrical problems are caused by bad connections.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=243194#243194
Message 12
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| Subject: | Re: Tunnel grounding |
Thanks Bill,
I appreciate your suggestions, but I am still hoping that Bob also chimes in before
I finish out the tunnel.
Best,
--------
Myron Nelson
Mesa, AZ
Emp completed, legacy build fuse in progress
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=243208#243208
Message 13
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| Subject: | Arinc 429 source to 429 receivers |
I need to connect one Arinc 429 source (GPS) to two receivers (MFD and TWX
670). The straight forward method would be to use butt splices with the
source on one side and both of the receivers on the other. Is there a
"best practice" technique for accomplishing this?
Kevin
Message 14
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| Subject: | Re: Tunnel grounding |
At 08:05 PM 5/8/2009, you wrote:
>
>Thanks Bill,
>
>I appreciate your suggestions, but I am still hoping that Bob also
>chimes in before I finish out the tunnel.
I thought I had responded to this but I don't
find the response on my computer here at home.
Perhaps I crafted something on a trip machine
and never got it sent. Anywho . . .
I am building an RV-10 and have settled for now on the one battery
two alternator scheme, and am planning to run a #2 ground wire from
the (rear) batt to a forest of grounds at the firewall.
Not really necessary in an all metal airplane but
works good . . .
My specific question for today has to do with grounding items in the
center tunnel, specifically, the fuel totalizer, fuel pump, flap
actuator, flap position selector, and a flap position sensor
(wouldn't it be great if those two could be combined into one geewhiz?)
At any rate, the question that I have on grounding those items is should I:
1. Ground each locally?
2. Run a separate ground for each to the front forest?
3. Run each to a mini forest in the tunnel that has its own ground
wire to either the front ground forest or back to the battery?
None of these are especially vulnerable to
ground loop noises so local grounds will probably
be fine. The super clean approach is separate
ground wires for each device to the forest
of tabs on the firewall.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 15
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| Subject: | Re: Arinc 429 source to 429 receivers |
At 10:34 PM 5/8/2009, you wrote:
>
>I need to connect one Arinc 429 source (GPS) to two receivers (MFD
>and TWX 670). The straight forward method would be to use butt
>splices with the source on one side and both of the receivers on
>the other. Is there a "best practice" technique for accomplishing this?
If you were running these lines for dozens of feet around
a big flying pig with dual 600A generators and a 5 hp
air conditioner motor, you might have some concerns for
process. In a small single engine aircraft, any neat
thing you want to do will work. Robustness of the
connections is the key. Solder would be good too.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
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