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jnmeade
Joined: 27 Sep 2012
Posts: 12
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 Posted: Fri Dec 20, 2019 4:47 am Post subject: Troubleshoot Generator |
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How do you troubleshoot a generator? Piper PA-22-150 Tri-Pacer 1955.
First incident. Noticed ammeter discharging in air. Landed.
Second incident. After a number of flights all OK, noticed ammeter showed
charge at run-up RPM, flew, noticed discharge about 30 minutes later.
Don't know when the generator went offline. Unloading various components
all indicated the ammeter correctly reflected their draw. Landed.
Third incident. Immediately after 2d, started engine and ammeter
immediately showed discharge.
Wires appear to be tightly connected but too hot for hands in engine
compartment for definitive check. Belt was good and had proper tension.
Initial calls to "old" mechanics and searching online shows very few
people are experienced in generator systems anymore.
My next step is to uncowl the plane and with the engine cool get my hands
in and check all wires for proper connection and condition.
I assume the ammeter is OK based on it's presentation.
If I can, I'm going to pull one or more brushes and inspect them.
I'd like to isolate the problem to either the voltage regulator or the
generator. How do I do that?
I intend to get the data plate information on the generator and determine
the make, model and type, but I don't have that information right now.
I'll post more info when I can but with holiday plans may be limited for a
while.
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argoldman(at)aol.com
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| Posted: Fri Dec 20, 2019 5:59 am Post subject: Troubleshoot Generator |
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Reminds me of an incident many years in a senica 1 I had. Left engine (could have been a generator) similar symptoms after many a& ps. Finally was sent to an electrical “specialist”. It turned out that there was a corroded switch due to water inclusion ( switches were below the little storm window or whatever it is called. I think it was the master switch but can’t be certain. That was about 40 yrs ago
Good luck on your hunt!
Rich
Sent from my iPhone
| Quote: | On Dec 20, 2019, at 6:43 AM, James Meade <jnmeade(at)southslope.net> wrote:
How do you troubleshoot a generator? Piper PA-22-150 Tri-Pacer 1955.
First incident. Noticed ammeter discharging in air. Landed.
Second incident. After a number of flights all OK, noticed ammeter showed charge at run-up RPM, flew, noticed discharge about 30 minutes later. Don't know when the generator went offline. Unloading various components all indicated the ammeter correctly reflected their draw. Landed.
Third incident. Immediately after 2d, started engine and ammeter immediately showed discharge.
Wires appear to be tightly connected but too hot for hands in engine compartment for definitive check. Belt was good and had proper tension.
Initial calls to "old" mechanics and searching online shows very few people are experienced in generator systems anymore.
My next step is to uncowl the plane and with the engine cool get my hands in and check all wires for proper connection and condition.
I assume the ammeter is OK based on it's presentation.
If I can, I'm going to pull one or more brushes and inspect them.
I'd like to isolate the problem to either the voltage regulator or the generator. How do I do that?
I intend to get the data plate information on the generator and determine the make, model and type, but I don't have that information right now.
I'll post more info when I can but with holiday plans may be limited for a while.
|
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echristley(at)att.net
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| Posted: Fri Dec 20, 2019 8:44 am Post subject: Troubleshoot Generator |
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Pull the generator. Mount it in a drill press. Adjust the drill press to run it at various speeds. Use a heat gun to simulate engine compartment conditions.
On Friday, December 20, 2019, 7:48:04 AM EST, James Meade <jnmeade(at)southslope.net> wrote:
--> AeroElectric-List message posted by: "James Meade" <jnmeade(at)southslope.net (jnmeade(at)southslope.net)>
How do you troubleshoot a generator? Piper PA-22-150 Tri-Pacer 1955.
First incident. Noticed ammeter discharging in air. Landed.
Second incident. After a number of flights all OK, noticed ammeter showed
charge at run-up RPM, flew, noticed discharge about 30 minutes later.
Don't know when the generator went offline. Unloading various components
all indicated the ammeter correctly reflected their draw. Landed.
Third incident. Immediately after 2d, started engine and ammeter
immediately showed discharge.
Wires appear to be tightly connected but too hot for hands in engine
compartment for definitive check. Belt was good and had proper tension.
Initial calls to "old" mechanics and searching online shows very few
people are experienced in generator systems anymore.
My next step is to uncowl the plane and with the engine cool get my hands
in and check all wires for proper connection and condition.
I assume the ammeter is OK based on it's presentation.
If I can, I'm going to pull one or more brushes and inspect them.
I'd like to isolate the problem to either the voltage regulator or the
generator. How do I do that?
I intend to get the data plate information on the generator and determine
the make, model and type, but I don't have that information right now.
I'll post more info when I can but with holiday plans may be limited forhttp://; &nb==================
http://www.matronics.com/Navigatonbsp; - MATRONICS WEB FORUMS -http://wiki.matronics.com[/url]
http://www.matron===
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ceengland7(at)gmail.com
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| Posted: Fri Dec 20, 2019 9:29 am Post subject: Troubleshoot Generator |
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On 12/20/2019 6:43 AM, James Meade wrote:
| Quote: | --> AeroElectric-List message posted by: "James Meade" <jnmeade(at)southslope.net> (jnmeade(at)southslope.net)
How do you troubleshoot a generator? Piper PA-22-150 Tri-Pacer 1955.
First incident. Noticed ammeter discharging in air. Landed.
Second incident. After a number of flights all OK, noticed ammeter showed charge at run-up RPM, flew, noticed discharge about 30 minutes later. Don't know when the generator went offline. Unloading various components all indicated the ammeter correctly reflected their draw. Landed.
Third incident. Immediately after 2d, started engine and ammeter immediately showed discharge.
Wires appear to be tightly connected but too hot for hands in engine compartment for definitive check. Belt was good and had proper tension.
Initial calls to "old" mechanics and searching online shows very few people are experienced in generator systems anymore.
My next step is to uncowl the plane and with the engine cool get my hands in and check all wires for proper connection and condition.
I assume the ammeter is OK based on it's presentation.
If I can, I'm going to pull one or more brushes and inspect them.
I'd like to isolate the problem to either the voltage regulator or the generator. How do I do that?
I intend to get the data plate information on the generator and determine the make, model and type, but I don't have that information right now.
I'll post more info when I can but with holiday plans may be limited for a while.
|
Assuming wiring integrity, You're down to the switch, generator brushes/internal connections, and the regulators internal connections. If you still have the the original style regulator on a plane of that age, it would have what amounts to a handful of mechanical relays in it.
[img]cid:part1.47DF85ED.9AFEED52(at)gmail.com[/img]
If the contacts are starting to burn/corrode, it'll cause random failures. You might find that you can remove the cover to inspect the contacts.
Charlie
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nuckolls.bob(at)aeroelect
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| Posted: Fri Dec 20, 2019 7:02 pm Post subject: Troubleshoot Generator |
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At 06:43 AM 12/20/2019, you wrote:
| Quote: | --> AeroElectric-List message posted by: "James Meade" <jnmeade(at)southslope.net>
How do you troubleshoot a generator? Piper PA-22-150 Tri-Pacer 1955. |
Took dual instruction from the one-and-only Rip Gooch
off Rawdon field in 1962 in one of those. Still one
of my favorite airplanes.
| Quote: | First incident. Noticed ammeter discharging in air. Landed.
Second incident. After a number of flights all OK, noticed ammeter showed
charge at run-up RPM, flew, noticed discharge about 30 minutes later.
Don't know when the generator went offline. Unloading various components
all indicated the ammeter correctly reflected their draw. Landed.
Third incident. Immediately after 2d, started engine and ammeter
immediately showed discharge. |
The most probable cause is brushes worn down beyond
limits. These should be part of the annual inspection
for wear limits. If the regulator is an 'original'
electro-mechnanical, then it's suspect . . . and if
very old . . . probably needs replacing 'just because.
It's no surprise that few mechanics can deal with
these old machines 'legally' . . . they don't
have practice, knowledge or documentation. B&C
probably has an STC for an L40 alternator installation.
Yeah, it would be 'nice' to keep it 'stock' . . . but
it's the best upgrade you could do for this venerable
Bob . . .
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JB Soar
Joined: 19 Apr 2019
Posts: 14
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| Posted: Fri Dec 20, 2019 8:18 pm Post subject: Troubleshoot Generator |
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One can inspect/replace the brushes, but, really, after many decades of service, the generator likely wore out due to corrosion of the internal parts. Bearings slowly fail, the brushes then wear at a more rapid rate. If the generator was serviced/replaced, this was likely done in the 70s or 80s... True: There are very few mechanics or shops that can service this generator. An alternator, legally installed via an STC, and a new battery, will likely solve all the problems. The alternator will likely be lighter than the generator, and the aircraft's Weight & Balance will need to be updated. This is an easy task... Install a new belt as well. That might well come in the kit...
On Fri, Dec 20, 2019 at 9:07 PM Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 06:43 AM 12/20/2019, you wrote:
| Quote: | --> AeroElectric-List message posted by: "James Meade" <jnmeade(at)southslope.net (jnmeade(at)southslope.net)>
How do you troubleshoot a generator? Piper PA-22-150 Tri-Pacer 1955. |
Took dual instruction from the one-and-only Rip Gooch
off Rawdon field in 1962 in one of those. Still one
of my favorite airplanes.
| Quote: | First incident. Noticed ammeter discharging in air. Landed.
Second incident. After a number of flights all OK, noticed ammeter showed
charge at run-up RPM, flew, noticed discharge about 30 minutes later.
Don't know when the generator went offline. Unloading various components
all indicated the ammeter correctly reflected their draw. Landed.
Third incident. Immediately after 2d, started engine and ammeter
immediately showed discharge. |
The most probable cause is brushes worn down beyond
limits. These should be part of the annual inspection
for wear limits. If the regulator is an 'original'
electro-mechnanical, then it's suspect . . . and if
very old . . . probably needs replacing 'just because.
It's no surprise that few mechanics can deal with
these old machines 'legally' . . . they don't
have practice, knowledge or documentation. B&C
probably has an STC for an L40 alternator installation.
Yeah, it would be 'nice' to keep it 'stock' . . . but
it's the best upgrade you could do for this venerable
Bob . . .
|
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http://www.matronics.com/Navigator?AeroElectric-List |
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skywagon185(at)gmail.com
Guest
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| Posted: Sat Dec 21, 2019 10:20 am Post subject: Troubleshoot Generator |
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Generator.... It sure sounds like it is heat related...
* if the brushes are quite worn/short, they may stay in contact with the commutator but, when the unit gets hot, the brush "holder/spring" might hangup and the short brushes don't make contact.
* One of the major internal wires may have a break; a very fine one. Cold the break does not fault the circuit, but, hot the break opens. Had experience with that one on a Chrysler based engine alternator. A very seasoned mechanic had seen the fault before. Where one end of a heavy stator wire was swaged into the alternator case, it developed a very "fine" crack. Would operate fine when cold, and stop, crack opened, when hot.
On Fri, Dec 20, 2019 at 9:34 AM Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:
| Quote: | On 12/20/2019 6:43 AM, James Meade wrote:
| Quote: | --> AeroElectric-List message posted by: "James Meade" <jnmeade(at)southslope.net> (jnmeade(at)southslope.net)
How do you troubleshoot a generator? Piper PA-22-150 Tri-Pacer 1955.
First incident. Noticed ammeter discharging in air. Landed.
Second incident. After a number of flights all OK, noticed ammeter showed charge at run-up RPM, flew, noticed discharge about 30 minutes later. Don't know when the generator went offline. Unloading various components all indicated the ammeter correctly reflected their draw. Landed.
Third incident. Immediately after 2d, started engine and ammeter immediately showed discharge.
Wires appear to be tightly connected but too hot for hands in engine compartment for definitive check. Belt was good and had proper tension.
Initial calls to "old" mechanics and searching online shows very few people are experienced in generator systems anymore.
My next step is to uncowl the plane and with the engine cool get my hands in and check all wires for proper connection and condition.
I assume the ammeter is OK based on it's presentation.
If I can, I'm going to pull one or more brushes and inspect them.
I'd like to isolate the problem to either the voltage regulator or the generator. How do I do that?
I intend to get the data plate information on the generator and determine the make, model and type, but I don't have that information right now.
I'll post more info when I can but with holiday plans may be limited for a while.
|
Assuming wiring integrity, You're down to the switch, generator brushes/internal connections, and the regulators internal connections. If you still have the the original style regulator on a plane of that age, it would have what amounts to a handful of mechanical relays in it.
[img]cid:16f29a45d051784666c1[/img]
If the contacts are starting to burn/corrode, it'll cause random failures. You might find that you can remove the cover to inspect the contacts.
Charlie
|
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
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| Viewed: |
3577 Time(s) |
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