Today's Message Index:
----------------------
1. 04:36 AM - Alternator problem? (donjohnston)
2. 05:50 AM - Re: Alternator problem? (user9253)
3. 08:25 AM - Re: Alternator problem? (Jeff)
4. 10:06 AM - Re: Alternator problem? (donjohnston)
5. 11:33 AM - Re: Re: Alternator problem? (Jeff Luckey)
6. 11:58 AM - GNS430W and TruTrak AP (Bill Bradburry)
7. 12:35 PM - Re: GNS430W and TruTrak AP (user9253)
8. 01:05 PM - Re: GNS430W and TruTrak AP (Robert L. Nuckolls, III)
9. 05:00 PM - Re: Re: Alternator problem? (Robert L. Nuckolls, III)
Message 1
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| Subject: | Alternator problem? |
I'm in the process of trying to track down an over voltage fault.
So far the engine runs that I've been doing have been relatively short duration
(mostly around 5-10min) while I'm getting the engine dialed in. On about 4 occasions
I've noticed the alternator circuit has faulted for "over voltage".
I'm running a 28v electrical system
VP-X Pro
B&C LR3C voltage regulator
Kelly Aerospace 50a alternator
Continental IO-550 engine.
Vertical Power and B&C have had me check a number things. All checks have shown
voltage levels, drops and wire resistance to be well within parameters.
B&C is recommending to pull the alternator and have it checked.
I"m just wondering if anyone has run into anything similar with these alternators
before I pull it ship it out.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=444057#444057
Message 2
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| Subject: | Re: Alternator problem? |
I think it is more likely that there is a bad (intermittent) connection or faulty
voltage regulator than a problem with the alternator. The best way to find
a bad connection is to make voltage measurements when the circuit is under heavy
load. A high wattage lamp can be used to temporarily load the circuit for
voltage testing. Particular attention should be given to LR3C terminals 6 and
7 and the associated wiring. If a high wattage lamp is connected between terminals
6 & 7, the voltage between those two terminals should be close to battery
voltage.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=444058#444058
Message 3
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| Subject: | Re: Alternator problem? |
Don,
First step is to determine if you are actually experiencing a fault or just a bad
indication.
Which system is giving you the over voltage fault error? The VP, an over voltage
module, something else?
Do you have a digital volt meter that remembers the highest peak voltage?
-Jeff
Sent from my iPad
> On Jun 26, 2015, at 04:34, donjohnston <don@velocity-xl.com> wrote:
>
>
> I'm in the process of trying to track down an over voltage fault.
>
> So far the engine runs that I've been doing have been relatively short duration
(mostly around 5-10min) while I'm getting the engine dialed in. On about 4
occasions I've noticed the alternator circuit has faulted for "over voltage".
>
> I'm running a 28v electrical system
> VP-X Pro
> B&C LR3C voltage regulator
> Kelly Aerospace 50a alternator
> Continental IO-550 engine.
>
> Vertical Power and B&C have had me check a number things. All checks have shown
voltage levels, drops and wire resistance to be well within parameters.
>
> B&C is recommending to pull the alternator and have it checked.
>
> I"m just wondering if anyone has run into anything similar with these alternators
before I pull it ship it out.
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=444057#444057
>
>
>
>
>
>
>
>
>
>
Message 4
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| Subject: | Re: Alternator problem? |
As it has been explained to me, the voltage regulator is determining the fault.
The VP-X is reporting the fault.
My meter has a hold feature but it's manual, not a peak hold.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=444069#444069
Message 5
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| Subject: | Re: Alternator problem? |
Don,
That regulator uses the "crowbar" technique to handle an over-voltage condi
tion.=C2- Which means that it will pop its own circuit breaker to shut it
self off when buss voltage gets too high.
So, is it the case that the electronic circuit breaker in the VP-X which fe
eds the regulator is "popping"?=C2- (I'm not very familiar w/ the VP-X so
I don't know how it indicates when one of its electronic circuit breakers
pops.)
Does the VP-X have an alarm channel for Over-Voltage?=C2- If so, was that
alarm triggered?
-Jeff
On Friday, June 26, 2015 10:16 AM, donjohnston <don@velocity-xl.com> w
rote:
m>
As it has been explained to me, the voltage regulator is determining the fa
ult. The VP-X is reporting the fault.
My meter has a hold feature but it's manual, not a peak hold.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=444069#444069
-
S -
-
=C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin.
Message 6
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| Subject: | GNS430W and TruTrak AP |
What happens to the voltage on the essential buss if it is loaded too
heavily and the diode does not have a heat sink installed?
I am having my radio and my autopilot reset from time to time in flight and
I suspect that the voltage on the essential buss is dropping to a level that
causes this. I plan to check the voltage on the buss next time I am at the
airport to try and confirm the voltage idea.
What can cause the voltage to drop if that is the problem? High resistance
connections? What else should I check?
Bill
Message 7
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| Subject: | Re: GNS430W and TruTrak AP |
If the diode is too hot to touch, it should have a heat sink.
It is unlikely that normal current through a diode will drop the voltage enough
to cause avionics to reboot. More likely is a loose connection.
Does the problem occur while the ebus switch is on?
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=444074#444074
Message 8
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| Subject: | Re: GNS430W and TruTrak AP |
At 01:56 PM 6/26/2015, you wrote:
><bbradburry@verizon.net>
>
>What happens to the voltage on the essential buss if it is loaded too
>heavily and the diode does not have a heat sink installed?
>
>I am having my radio and my autopilot reset from time to time in flight and
>I suspect that the voltage on the essential buss is dropping to a level that
>causes this. I plan to check the voltage on the buss next time I am at the
>airport to try and confirm the voltage idea.
>
>What can cause the voltage to drop if that is the problem? High resistance
>connections? What else should I check?
Diodes don't do that. Your data acquisition and
diagnosis problem is not unlike that described
in another thread on this forum theorizing about
root cause of an OV trip.
Transient events are . . . just that . . .SHORT.
Probability of capturing data with the ordinary
shop tools that will flashlight a path to discovery
is slim.
Does your diode get too hot to touch? What is it
mounted to and what kind of diode? Try flying with
the alternate feed switch ON thus bypassing the
normal feed through the diode.
In the mean time, I'll continue a recently resurrected
notion of devising some data capture tools that can
be easily acquired or perhaps mailed around. Playing
'swap-tronics' until the problem goes away is not
very professional or satisfying.
Bob . . .
Message 9
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| Subject: | Re: Alternator problem? |
At 12:05 PM 6/26/2015, you wrote:
>
>As it has been explained to me, the voltage regulator is determining
>the fault. The VP-X is reporting the fault.
>
>My meter has a hold feature but it's manual, not a peak hold.
If we were conducting this investigation
in B-31 at Beech (Flight Test) we would
get out a data acquisition system capable
gathering 5 channels of voltage at 2%
or better accuracy for 100 samples per
second or faster.
Monitor battery voltage at the battery
Monitor B-terminal voltage at the alternator
Monitor Alternator Field voltage at the
alternator
Monitor Bus Sense voltage at the regulator
Monitor Bus Voltage at the Regulator.
Then go fly and see if the problem will
duplicate.
The data traces will reveal how the major
players behave before, during and after
the event . . . and probably narrow the
options for root cause.
That regulator has 'selective ov trip'.
When an ov condition is detected, the field
voltage from the regulator MUST be high
for the ov trip to be triggered.
This logic allows more than one alternator
to parallel on a bus and avoid an ov trip
for both alternators should only one of them
mis-behave. Knowing what I do about the
hardware, it seems most likely that the ov
sensing system is being irritated by some
phenomenon in the system.
In the early days of crowbar ov system
development, we were chagrined to discover
that SOME airplanes had extra-ordinarily
significant transient sources that would
nuisance trip our regulators. Regulars
with years of satisfactory service on
thousands of airframes.
I'm not aware of recent examples of
'extra ordinary irritation' but I wouldn't
discount it.
Can you pair the ov trip even with any particular
action elsewhere in the system?
Bob . . .
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