Alternator load distribution in a Baron

[Viperdoc]

My 1980 B-55 has uneven load distribution on the two alternators, with the
right side consistently reading around 15% lower than the left.

Is this an indication of a problem with the alternator like a bad diode, or
is this normal operating behavior?

[Bill Hale]

"Viperdoc" > wrote in message >...
> My 1980 B-55 has uneven load distribution on the two alternators, with the
> right side consistently reading around 15% lower than the left.
>
> Is this an indication of a problem with the alternator like a bad diode, or
> is this normal operating behavior?

They match within 15%? That's great. Even tho the POH suggests better.

You should check to verify that each can handle the load by itself, even at
fairly low RPM like 1500. That will eliminate the possibility of
failed diodes.

You do switch between regulators on each trip, don't you? That
way you know both regulators work. T'aint redundant otherwise.

Bill Hale, BPPP instructor

[Nathan Young]

"Viperdoc" > wrote in message >...
> My 1980 B-55 has uneven load distribution on the two alternators, with the
> right side consistently reading around 15% lower than the left.
>
> Is this an indication of a problem with the alternator like a bad diode, or
> is this normal operating behavior?

I had a similar problem with a Seneca. Except is was more like 80/20.
Turned out to be the voltage regulators being set higher on one
alternator than another.

-Nathan

[Viperdoc]

Yes, I switch the voltage regulator on every flight. The concerns that I
voiced regarding the alternator load came from an article in the American
Bonanza Society magazine, where another Baron owner saw similar behavior.
This article suggested that it might be a bad diode in the weaker
alternator.

As a matter of fact, I called the ABS today, and they suggested that the
observed difference could be due to a poor ground, and suggested
investigation of the same. I hope to do this in the near future.

Thanks.

[David Lesher]

"Viperdoc" > writes:

>Yes, I switch the voltage regulator on every flight. The concerns that I
>voiced regarding the alternator load came from an article in the American
>Bonanza Society magazine, where another Baron owner saw similar behavior.
>This article suggested that it might be a bad diode in the weaker
>alternator.

>As a matter of fact, I called the ABS today, and they suggested that the
>observed difference could be due to a poor ground, and suggested
>investigation of the same. I hope to do this in the near future.

Could be bad grounds. Could be bad diodes.

But unless the two voltage regulators EXACTLY track {and they never
do} one will work harder than the other. That's life.

You can test for bad diodes with a fair degree of success as follows.
With one alternator on line at idle, load it down, say the landing
lights. Listen carefully in your headset for whine, dependent on
RPM. Then swap to the other alternator. If one is missing a diode,
it likely will have far more audible whine than the other.

(I'm having a hard time picturing how you swap regulators. Does
this aircraft use one regulator for both alternators???)

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

[Viperdoc]

The B-55 has two voltage regulators, which are switchable from inside the
cockpit. I plan on flying locally tomorrow, and will check the diodes for
each alternator.

[Viperdoc]

Just thinking: does cutting the alternator (belt driven) in and out with the
engine running damage anything?

[PaulaJay1]

In article >, "Viperdoc"
> writes:

>Just thinking: does cutting the alternator (belt driven) in and out with the
>engine running damage anything?

I hope not. I start my Archer with the Gen field off and then turn it on after
engine start.

Chuck