Today's Message Index:
----------------------
1. 04:47 AM - Troubleshoot Generator (James Meade)
2. 05:59 AM - Re: Troubleshoot Generator (A R Goldman)
3. 08:44 AM - Re: Troubleshoot Generator (Ernest Christley)
4. 09:29 AM - Re: Troubleshoot Generator (Charlie England)
5. 02:25 PM - Re: One battery/two alternators IFR z-diagram (Robert L. Nuckolls, III)
6. 03:03 PM - Re: One battery/two alternators IFR z-diagram (Robert L. Nuckolls, III)
7. 03:46 PM - Re: One battery/two alternators IFR z-diagram (Sebastien)
8. 04:16 PM - Re: One battery/two alternators IFR z-diagram (user9253)
9. 07:02 PM - Re: Troubleshoot Generator (Robert L. Nuckolls, III)
10. 08:00 PM - Re: One battery/two alternators IFR z-diagram (Michael Burbidge)
11. 08:18 PM - Re: Troubleshoot Generator (John B)
12. 08:30 PM - Re: Switch ratings? (David Saylor)
Message 1
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| Subject: | Troubleshoot Generator |
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.
Message 2
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| Subject: | Re: Troubleshoot Generator |
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 cant be certain. That was about
40 yrs ago
Good luck on your hunt!
Rich
Sent from my iPhone
> On Dec 20, 2019, at 6:43 AM, James Meade <jnmeade@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.
>
>
>
Message 3
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| Subject: | Re: Troubleshoot Generator |
Pull the generator.=C2- Mount it in a drill press.=C2- Adjust the dril
l press to run it at various speeds.=C2- Use a heat gun to simulate engin
e compartment conditions.
On Friday, December 20, 2019, 7:48:04 AM EST, James Meade <jnmeade@sout
hslope.net> wrote:
.net>
How do you troubleshoot a generator?=C2- Piper PA-22-150 Tri-Pacer 1955.
First incident.=C2- Noticed ammeter discharging in air.=C2- Landed.
Second incident.=C2- After a number of flights all OK, noticed ammeter sh
owed=C2-
charge at run-up RPM, flew, noticed discharge about 30 minutes later.=C2-
Don't know when the generator went offline.=C2- Unloading various compone
nts=C2-
all indicated the ammeter correctly reflected their draw.=C2- Landed.
Third incident.=C2- Immediately after 2d, started engine and ammeter=C2
-
immediately showed discharge.
Wires appear to be tightly connected but too hot for hands in engine=C2-
compartment for definitive check.=C2- Belt was good and had proper tensio
n.
Initial calls to "old" mechanics and searching online shows very few=C2-
people are experienced in generator systems anymore.
My next step is to uncowl the plane and with the engine cool get my hands
=C2-
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=C2
-
generator.=C2- How do I do that?
I intend to get the data plate information on the generator and determine
=C2-
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
=C2-
while.
=C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin.
-
S -
WIKI -
-
=C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin.
Message 4
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| Subject: | Re: Troubleshoot Generator |
On 12/20/2019 6:43 AM, James Meade wrote:
> <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
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| Subject: | Re: One battery/two alternators IFR z-diagram |
At 08:26 PM 12/18/2019, you wrote:
>After doing some reading on the FAQ list, it looks like I should
>consider the Z-13/8 with the Z-25 excitation mod, or else the Z-14.
>I think I also now understand one of the drawbacks of Z-12
>architecture is if the battery contactor fails, both alternators go offline.
>
>Michael-
That's generally not true with modern alternators . . .
and only a few of the legacy alternators.
It's true that many alternators will not come
online without a battery present . . .but once
running, they'll hum along oblivious to battery
being there or not.
With HEAVY inrush loads like klieg-lights in the
wings or hydraulic pump motors. It was theoretically
possible to stall an alternator . . .from which
recovery would be impossible unless a battery were
present.
Such loads are rare in our neighborhood of the
GA community. Contactor failure in flight
is exceedingly rare . . . never heard of one . . .
but ANY change to engine cranking performance
on the GROUND calls for investigation . . . you
might have a contactor getting tired.
But if the engine starts right smartly then
you've 'preflighted' the contactor . . . probability
of loosing it in the next 3 hours of operation
is nil.
Z-12 is flying in hundreds if not thousands of
TC aircraft and they don't even have an e-bus.
If you've got a ROBUST standby alternator like
the contemporary SD20 machines, then the need
for load-shedding with loss of main alternator
is minimal if non-existent . . . hence, the need
for a refined load-shedding protocol is negated.
Of course, this should all be CONFIRMED by
completing the very first design document needed
for artful crafting of your system . . . the LOAD
ANALYSIS.
If it were my airplane, I'd go for Z12 with no
ebus and a well maintained battery. The auto-switch
feature for Z-12 is not necessary for flight
safety. I'd run an LR3 on the main alternator
and a generic VR166 on the standby alternator.
Leave standby alternator OFF until needed as
annunciated by a low volts warning.
Bob . . .
Message 6
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| Subject: | Re: One battery/two alternators IFR z-diagram |
>
>What is there a recommended replacement architecture for the z-13/20?
Z13/8 was crafted with the notion of offering
a robust (meaning unlimited electrical endurance
in the alt-out mode) plan-b for loss of main alternator
assuming running loads can be reduced to 10A
or less . . . which is the capability of
the SD8.
I fiddled with the idea of a Z13/20 waayyy
back when . . . at time when the operating
philosophy for the SD20 called for b-lead
current sensing and cockpit indications
for reducing load to values at or below
the 'rated' output of the alternator.
This made the FAA happy . . . but in retrospect
was totally unnecessary. The SD20 has
a pedigree based on a 40A, automotive,
belt driven alternator (B&C's L40).
In a Lycoming installation, it runs
at 10KRPM or better, may indeed be expected
to produce 40A under some conditions
and is belt-driven which produces significant
axial loading on the bearings.
As an SD20, it's DERATED not for any physical
design limits . . . but because on the
vacuum pump pad it isn't driven at much
more than 3900 rpm. So in fact, you cannot
physically 'overload' this alternator to the
extend that functionality is at risk.
Its output sags and it's physically incapable
of producing the same output as the mother-machine
just 'cause it's not turning fast enough.
In years since, materials and processes for
the raw-stock have improved such that the
SD20 is now rated at more than 20A on a
pad drive.
The Z13/8 philosophy for minimizing running
loads while under standby power is not
especially valid for EITHER a Z12 or Z13/20
application.
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. The best indicator of loading the standby
alternator too hard is depression of bus
voltage below 13.0 volts. Given the number
of voltmeters in most airplanes today, the
value of a over-current, under-voltage sensing
regulator on the standby system seems something
of overkill.
Modern electronics and lighting have made it
possible to craft even an IFR capable machine
with running loads below the output capability
of a pad-driven SD20.
Have I overlooked anything here? Considered
critical review is most welcome . . .
Bob . . .
Message 7
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| Subject: | Re: One battery/two alternators IFR z-diagram |
Speaking strictly for my applications Bob (VFR and IFR AB, some of which
have electrically dependent engines), I totally agree. My ideal system is
not bulletproof or dispatcheable after one or more failures. My ideal
system is as simple and cheap as possible, while allowing for comfortable
termination of flight after a failure.
As soon as the bus voltage sags below 13.8v, red lights start flashing in
multiple places. Once this happens there is a checklist to follow in each
airplane, and manually changing the alternator switch from main to aux is
no big deal. 20A is sufficient for comfortable termination of flight, or
even load shedding and continuation of flight in many circumstances.
I like the idea of an endurance bus, but have never implemented it because
the added complexity was not justified by the benefits.
On Fri, Dec 20, 2019, 15:09 Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
>
> What is there a recommended replacement architecture for the z-13/20?
>
>
> Z13/8 was crafted with the notion of offering
> a robust (meaning unlimited electrical endurance
> in the alt-out mode) plan-b for loss of main alternator
> assuming running loads can be reduced to 10A
> or less . . . which is the capability of
> the SD8.
>
> I fiddled with the idea of a Z13/20 waayyy
> back when . . . at time when the operating
> philosophy for the SD20 called for b-lead
> current sensing and cockpit indications
> for reducing load to values at or below
> the 'rated' output of the alternator.
>
> This made the FAA happy . . . but in retrospect
> was totally unnecessary. The SD20 has
> a pedigree based on a 40A, automotive,
> belt driven alternator (B&C's L40).
> In a Lycoming installation, it runs
> at 10KRPM or better, may indeed be expected
> to produce 40A under some conditions
> and is belt-driven which produces significant
> axial loading on the bearings.
>
> As an SD20, it's DERATED not for any physical
> design limits . . . but because on the
> vacuum pump pad it isn't driven at much
> more than 3900 rpm. So in fact, you cannot
> physically 'overload' this alternator to the
> extend that functionality is at risk.
> Its output sags and it's physically incapable
> of producing the same output as the mother-machine
> just 'cause it's not turning fast enough.
>
> In years since, materials and processes for
> the raw-stock have improved such that the
> SD20 is now rated at more than 20A on a
> pad drive.
>
> The Z13/8 philosophy for minimizing running
> loads while under standby power is not
> especially valid for EITHER a Z12 or Z13/20
> application.
>
> 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. The best indicator of loading the standby
> alternator too hard is depression of bus
> voltage below 13.0 volts. Given the number
> of voltmeters in most airplanes today, the
> value of a over-current, under-voltage sensing
> regulator on the standby system seems something
> of overkill.
>
> Modern electronics and lighting have made it
> possible to craft even an IFR capable machine
> with running loads below the output capability
> of a pad-driven SD20.
>
> Have I overlooked anything here? Considered
> critical review is most welcome . . .
>
> Bob . . .
>
Message 8
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| Subject: | Re: One battery/two alternators IFR z-diagram |
> 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. The best indicator of loading the standby
> alternator too hard is depression of bus
> voltage below 13.0 volts. Given the number
> of voltmeters in most airplanes today, the
> value of a over-current, under-voltage sensing
> regulator on the standby system seems something
> of overkill.
> Modern electronics and lighting have made it
> possible to craft even an IFR capable machine
> with running loads below the output capability
> of a pad-driven SD20.
> Have I overlooked anything here? Considered
> critical review is most welcome . . .
> Bob . . .
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
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=493911#493911
Message 9
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| Subject: | Re: Troubleshoot Generator |
At 06:43 AM 12/20/2019, you wrote:
><jnmeade@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.
>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 . . .
Message 10
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| Subject: | Re: One battery/two alternators IFR z-diagram |
Thanks for the detailed response Bob. You=92ve probably responded to this q
uestion before. I looked for the archive of this mail list. But couldn=92t
find it. Is there an archive. I could swear I=92ve used it before.
Michael
From: "owner-aeroelectric-list-server@matronics.com" <owner-aeroelectric-li
st-server@matronics.com> on behalf of "Robert L. Nuckolls, III" <nuckolls.b
ob@aeroelectric.com>
m>
Subject: Re: AeroElectric-List: One battery/two alternators IFR z-diagram
What is there a recommended replacement architecture for the z-13/20?
Z13/8 was crafted with the notion of offering
a robust (meaning unlimited electrical endurance
in the alt-out mode) plan-b for loss of main alternator
assuming running loads can be reduced to 10A
or less . . . which is the capability of
the SD8.
I fiddled with the idea of a Z13/20 waayyy
back when . . . at time when the operating
philosophy for the SD20 called for b-lead
current sensing and cockpit indications
for reducing load to values at or below
the 'rated' output of the alternator.
This made the FAA happy . . . but in retrospect
was totally unnecessary. The SD20 has
a pedigree based on a 40A, automotive,
belt driven alternator (B&C's L40).
In a Lycoming installation, it runs
at 10KRPM or better, may indeed be expected
to produce 40A under some conditions
and is belt-driven which produces significant
axial loading on the bearings.
As an SD20, it's DERATED not for any physical
design limits . . . but because on the
vacuum pump pad it isn't driven at much
more than 3900 rpm. So in fact, you cannot
physically 'overload' this alternator to the
extend that functionality is at risk.
Its output sags and it's physically incapable
of producing the same output as the mother-machine
just 'cause it's not turning fast enough.
In years since, materials and processes for
the raw-stock have improved such that the
SD20 is now rated at more than 20A on a
pad drive.
The Z13/8 philosophy for minimizing running
loads while under standby power is not
especially valid for EITHER a Z12 or Z13/20
application.
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. The best indicator of loading the standby
alternator too hard is depression of bus
voltage below 13.0 volts. Given the number
of voltmeters in most airplanes today, the
value of a over-current, under-voltage sensing
regulator on the standby system seems something
of overkill.
Modern electronics and lighting have made it
possible to craft even an IFR capable machine
with running loads below the output capability
of a pad-driven SD20.
Have I overlooked anything here? Considered
critical review is most welcome . . .
Bob . . .
Message 11
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| Subject: | Re: Troubleshoot Generator |
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@aeroelectric.com> wrote:
> At 06:43 AM 12/20/2019, you wrote:
>
> jnmeade@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.
>
> 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 . . .
>
Message 12
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| Subject: | Re: Switch ratings? |
"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. The highest voltage feeds the device.
On Thu, Dec 19, 2019 at 9:16 AM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> A single feed endurance bus with a switch
> in the feeder . . . what 'lectro-whizzies
> run from this bus?
>
> Bob . . .
>
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