Today's Message Index:
----------------------
1. 04:59 AM - More Tri-Pacer Generator Info (James Meade)
2. 09:00 AM - Re: Architecture Question (was Switch ratings?) (Robert L. Nuckolls, III)
3. 09:20 AM - Re: More Tri-Pacer Generator Info (Robert L. Nuckolls, III)
4. 10:20 AM - Re: Troubleshoot Generator (skywagon185guy .)
5. 08:35 PM - Re: Re: One battery/two alternators IFR z-diagram (Rick Beebe)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | More Tri-Pacer Generator Info |
The generator is an Aerotechlou rebuilt and installed in 2014. It is
almost certainly a Delco Remy 35 amp and I'm assuming it is a type "A"
circuit as described in their literature. We're trying to run down the
paperwork. There is a vision port which can be viewed and from that the
brushes look well seated and the commutator is clean and serviceable. The
VR is a Zentronic G1350 which looks to be of modern design (no mechanical
points). Troubleshooting on the Aerotechlou site says remove the field
wire and jumper the field terminal to aircraft ground. Remove the
armature wire and measure the voltage to ground with a DC voltmeter and
the engine running. The voltage should follow engine RPM.
I'm going to do this by taking the wires off of the voltage regulator,
which is on the firewall, instead of the governor. The governor is
virtually inaccessible. To get at it one must pull the prop and the front
cowl. Not inclined to do that until it's the only choice. I understand
this does not isolate the wires, but if the wires are the problem the prop
and cowl have to come off anyway or get someone with smaller fingers.
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Architecture Question (was Switch ratings?) |
At 10:29 PM 12/20/2019, you wrote:
>"Aircraft Power 2" inputs for nine devices
>(almost everything), plus AP servos and trim. Endurance and anti-sag.
>
>As I understand it, Aircraft Power 1 and
>Aircraft Power 2 are "dioded" (Garmin's word)
>apart.=C2 The highest voltage feeds the device.
Okay, you've lost me. Need to see an architecture
drawing.
Bob . . .
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: More Tri-Pacer Generator Info |
At 06:56 AM 12/21/2019, you wrote:
><jnmeade@southslope.net>
>
>The generator is an Aerotechlou rebuilt and installed in 2014. It is
>almost certainly a Delco Remy 35 amp and I'm assuming it is a type "A"
>circuit as described in their literature. We're trying to run down the
>paperwork. There is a vision port which can be viewed and from that the
>brushes look well seated and the commutator is clean and serviceable. The
>VR is a Zentronic G1350 which looks to be of modern design (no mechanical
>points).
EXCELLENT! An updated system . . . nice that your
vintage bird can stay as close to original as
possible/practical.
> Troubleshooting on the Aerotechlou site says remove the field
>wire and jumper the field terminal to aircraft ground. Remove the
>armature wire and measure the voltage to ground with a DC voltmeter and
>the engine running. The voltage should follow engine RPM.
An excellent data point . . . but this only says
the brushes are 'mostly' in good contact. Since
system charging currents flow in the brushes,
a voltmeter falls way short of duplicating
a 'proof load'. When you do this test, add
at least one, if not 2, 55 Watt head lamps to
the load. Adding this load makes flaky brushes
more likely to demonstrate their problems.
And this test isn't a sure bet . . . you've described
situations where the system DID produce adequate power
for significant periods of time . . .
>I'm going to do this by taking the wires off of the voltage regulator,
>which is on the firewall, instead of the governor. The governor is
>virtually inaccessible.
Good idea.
> To get at it one must pull the prop and the front
>cowl. Not inclined to do that until it's the only choice. I understand
>this does not isolate the wires, but if the wires are the problem the prop
>and cowl have to come off anyway or get someone with smaller fingers.
Sounds like your on a promising track to discovering
root cause. Run the traps on the manufacturer's
recommended troubleshooting procedures. If no
joy, get back here and we can offer further advise
on how to track down the problem.
Do you put a lot of hours on this a/c? That generator, under
moderate loads should have a brush life on the order
of 200-300 hours . . . maybe better. But your inspection
window should confirm/deny brush wear as the problem.
The symptoms you describe DO suggest that it's
a brush problem. If the VR is solid state, then
probability of failure is low . . . probability
of intermittent failure lower still . . . but
not zero in any case.
Keep us appraised of your progress . . . we don't
often get to witness the detective work on
vintage problems!
Bob . . .
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Troubleshoot Generator |
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@gmail.com>
wrote:
> On 12/20/2019 6:43 AM, James Meade wrote:
>
> <jnmeade@southslope.net> <jnmeade@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.
>
>
> 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
>
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: One battery/two alternators IFR z-diagram |
On 12/20/2019 7:15 PM, user9253 wrote:
>
> So as mentioned in my post of a few mintues
> ago, I think I'm going to revise Z-12 to (1)
> remove the Endurance Bus and (2) replace the
> standby regulator with something simple and
> cheap.
> Great idea Bob. Simpler is better.
> Many VFR sport planes do not even need a standby alternator.
> Now if we could just convince builders to NOT install an avionics switch.
>
> --------
> Joe Gores
I'm sold on both counts. I'm turning my traditional 6-pack VFR GlaStar
into an all-glass IFR plane and I'm wiring it using Z-12 with no
endurance bus and no avionics master. I repurposed its hole for the
pitot heat switch.
--Rick
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|