Different plane, same fix

When we flew our '75 Warrior, it developed a problem with the
alternator going off-line in flight. This was preceeded by the
ammeter needle bouncing crazily and finally pegging at 60 amps.

I fixed that problem by spending an hour tracing all the electrical
lines, and tightening connections. The main culprit was a wire
connector that was screwed into the backside of the alternator with a
simple phillips screw -- no safety wire, no loc-tite, no nuthin'.
Looked like a ground wire to me, but I'm no mechanic.

I turned it a good two and half turns, and the problem went away,
never to return. We sold the plane in '02.

Recently, Atlas developed a nasty, annoying whine in the headphones.
This developed immediately after I had removed the PS Engineering CD/
Intercom for some panel maintenance, so I naturally assumed that they
were related.

No amount of re-seating, cleaning, wiggling had any effect. My
frustration was mounting.

Then, this past Sunday, I decided to chang the oil after our return
flight from the Cherokee Pilots Association fly-in. It was Fathers
Day, it was 100 degrees in the hangar, and we were both melting, but I
decided to de-cowl the plane in order to make the oil change easier,
and to trace the wiring -- just in case it was another loose
connection somewhere.

Of course, the first place I looked was the backside of the
alternator, and, lo and behold, the same damned wire was loose! A
few turns to tighten, and voila! -- no more whine. (I traced the rest
of the wiring, while I was at it, and found a couple of broken zip
ties, and one broken wire -- a lead going to one of my cylinder
heaters. It's broken right where it goes into the cylinder -- THAT
looks like absolutely no fun to repair...)

Anyway, what should I put on this stupid screw to stop it from
vibrating loose? LocTite? Another lock washer? There's no way to
safety wire it...

Thanks!
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination

"Jay Honeck" wrote in message
oups.com...
When we flew our '75 Warrior, it developed a problem with the
alternator going off-line in flight. This was preceeded by the
ammeter needle bouncing crazily and finally pegging at 60 amps.

I fixed that problem by spending an hour tracing all the electrical
lines, and tightening connections. The main culprit was a wire
connector that was screwed into the backside of the alternator with a
simple phillips screw -- no safety wire, no loc-tite, no nuthin'.
Looked like a ground wire to me, but I'm no mechanic.

I turned it a good two and half turns, and the problem went away,
never to return. We sold the plane in '02.

Recently, Atlas developed a nasty, annoying whine in the headphones.
This developed immediately after I had removed the PS Engineering CD/
Intercom for some panel maintenance, so I naturally assumed that they
were related.

No amount of re-seating, cleaning, wiggling had any effect. My
frustration was mounting.

Then, this past Sunday, I decided to chang the oil after our return
flight from the Cherokee Pilots Association fly-in. It was Fathers
Day, it was 100 degrees in the hangar, and we were both melting, but I
decided to de-cowl the plane in order to make the oil change easier,
and to trace the wiring -- just in case it was another loose
connection somewhere.

Of course, the first place I looked was the backside of the
alternator, and, lo and behold, the same damned wire was loose! A
few turns to tighten, and voila! -- no more whine. (I traced the rest
of the wiring, while I was at it, and found a couple of broken zip
ties, and one broken wire -- a lead going to one of my cylinder
heaters. It's broken right where it goes into the cylinder -- THAT
looks like absolutely no fun to repair...)

Anyway, what should I put on this stupid screw to stop it from
vibrating loose? LocTite? Another lock washer? There's no way to
safety wire it...

Arc weld it.

On 06/20/07 08:54, Jay Honeck wrote:

[ snip ]


Anyway, what should I put on this stupid screw to stop it from
vibrating loose? LocTite? Another lock washer? There's no way to
safety wire it...

Thanks!

Can you get a bolt/screw that will fit the threads and which can
be safety wired? ... or would that not be an "approved" part?

Well if conductivity can be maintained, loctite (not red) should be
okay, used sparingly of course. Dare I say a blob of silicone over the
whole thing? Something harde seems scarey to use, like JB Weld or liquid
solder, epoxy glue and such. New lockwashers are probably in order.

I am going to go check my alternators tomorrow....

John

Jay Honeck wrote:

When we flew our '75 Warrior, it developed a problem with the
alternator going off-line in flight. This was preceeded by the
ammeter needle bouncing crazily and finally pegging at 60 amps.

I fixed that problem by spending an hour tracing all the electrical
lines, and tightening connections. The main culprit was a wire
connector that was screwed into the backside of the alternator with a
simple phillips screw -- no safety wire, no loc-tite, no nuthin'.
Looked like a ground wire to me, but I'm no mechanic.

I turned it a good two and half turns, and the problem went away,
never to return. We sold the plane in '02.

Recently, Atlas developed a nasty, annoying whine in the headphones.
This developed immediately after I had removed the PS Engineering CD/
Intercom for some panel maintenance, so I naturally assumed that they
were related.

No amount of re-seating, cleaning, wiggling had any effect. My
frustration was mounting.

Then, this past Sunday, I decided to chang the oil after our return
flight from the Cherokee Pilots Association fly-in. It was Fathers
Day, it was 100 degrees in the hangar, and we were both melting, but I
decided to de-cowl the plane in order to make the oil change easier,
and to trace the wiring -- just in case it was another loose
connection somewhere.

Of course, the first place I looked was the backside of the
alternator, and, lo and behold, the same damned wire was loose! A
few turns to tighten, and voila! -- no more whine. (I traced the rest
of the wiring, while I was at it, and found a couple of broken zip
ties, and one broken wire -- a lead going to one of my cylinder
heaters. It's broken right where it goes into the cylinder -- THAT
looks like absolutely no fun to repair...)

Anyway, what should I put on this stupid screw to stop it from
vibrating loose? LocTite? Another lock washer? There's no way to
safety wire it...

Thanks!
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination

Jay Honeck wrote:
Anyway, what should I put on this stupid screw to stop it from
vibrating loose? LocTite? Another lock washer? There's no way to
safety wire it...

New phillips screw, new external tooth lockwasher, loctite (medium grade
removable type), add it to the list of inspection items when the cowl is
off the airplane.

There may be a drilled head screw/bolt you could use, but you mentioned
there is no way to safety wire it.....I assume that means nothing on the
back of the alternator to wire it to.

Steve

Jay Honeck wrote:
I fixed that problem by spending an hour tracing all the electrical
lines, and tightening connections. The main culprit was a wire
connector that was screwed into the backside of the alternator with a
simple phillips screw -- no safety wire, no loc-tite, no nuthin'.
Looked like a ground wire to me, but I'm no mechanic.
SNIP
Anyway, what should I put on this stupid screw to stop it from
vibrating loose? LocTite? Another lock washer? There's no way to
safety wire it...

"Generally" there's only 2 wires on the alternator; the field wire from
the regulator, and the output. Ground is usually established through
the case of the alternator and associated bracket. If it was a
relatively thin wire, it was more likely that it was the field. If
that's the case, you defintely DON'T want to safety wire it. A fresh
lock washer, and if you absolutely must, a very small dab of Locktite.

There's always a chance that it was some sort of "extra" ground that
someone added, but if that being loose is causing a whine, it seems
like something else is also wrong (and the extra ground is covering it
up).

--- Jay


--

Jay Masino "Home is where My critters are"
http://www.JayMasino.com
http://www.OceanCityAirport.com
http://www.oc-Adolfos.com

PLEASE, NO LOCTITE. LOCTITE MEANS THAT YOU NEVER WANT TO REMOVE THE SCREW
AGAIN, which is going to play hell if the alternator itself ever craps out.

If it is a bare wire, then no lockwasher in the world will help. Put a crimp
terminal on the wire and then an INTERNAL TOOTH star or splitring
lockwasher. The order of assembly is alternator, crimp terminal,
lockwasher, screw.

Jim

--
"Dream as if you'll live forever. Live as if you'll die today."
--James Dean




"Jay Honeck" wrote in message
oups.com...
When we flew our '75 Warrior, it developed a problem with the
alternator going off-line in flight. This was preceeded by the
ammeter needle bouncing crazily and finally pegging at 60 amps.

Jay Honeck wrote:
When we flew our '75 Warrior, it developed a problem with the
alternator going off-line in flight. This was preceeded by the
ammeter needle bouncing crazily and finally pegging at 60 amps. [...]
The main culprit was a wire connector that was screwed into the
backside of the alternator with a simple phillips screw -- no safety
wire, no loc-tite, no nuthin'. Looked like a ground wire to me, but
I'm no mechanic.

Disclaimer: This is based on experience with ground vehicles and by
looking at the generator setup on a 182. I don't have an A&P; I don't
even have a TG&Y. Some of this may not be allowable owner maintenance.
Some of this may not be allowable on a certificated aircraft. Your
mileage may vary.

Sounds like the field wire to me. A loose ground wire would probably
tend to make the ammeter read less (discharge), rather then pegging at
max charge.

There are some variations, but in general, a generator or alternator
with external regulator will have three connections:

- Main output wire. This carries all of the current coming out of the
generator or alternator. Usually the fattest (thickest) wire on the
device, and often bolted on to a fairly substantial stud - 0.25"/6.3
mm or more diameter. The stud will be insulated from the metal case
of the machine.

- Field wire. The regulator turns this on and off to control how much
current the main wire puts out. This is a relatively thin wire (on
the order of 14 gauge or 1.5 mm^2) and may be bolted to a stud or
screwed to a metal terminal. The stud or screw will be relatively
small, like #8 or #10 (maybe 3 or 4 mm). The stud or terminal will
be insulated from the metal case of the machine.

- Ground connection. Often done through the mounting bolts, but some
may have a separate ground wire or strap. It will be at least as
thick as the field wire and possibly as thick as the main output wire.
It may also be a woven metal strap instead of a wire. This will be
bolted directly to the metal casing of the machine with no insulation.

Again, there are variations, but this is probably the most common setup
on older aircraft.

Of course, the first place I looked was the backside of the
alternator, and, lo and behold, the same damned wire was loose! A
few turns to tighten, and voila! -- no more whine [in radio audio].

Before you fiddle with this, make sure the master is off. For extra
safety, disconnect the battery negative cable.

Look at the place the screw goes into. Is there a plastic ring or boss
around it, insulating the screw from the case of the machine? If so,
then it's NOT a ground wire, and you CANNOT safety wire it to anything
that is grounded.

Also, look to see how contact is made. There should be a ring terminal
on the end of the wire. If there is a fairly substantial ring of metal
on the machine under the ring terminal, such that it contacts all of the
ring terminal all around, then that's probably where most of the
electrical contact happens, and the screw threads are just there to hold
it down. (If not, see "A" below.) In this case, I would consider this:
Get an aircraft-approved screw with the same thread as the existing screw,
plus a hex (internal or external) head. Also get an aircraft-approved
flat washer that fits the screw. You'll also need some brake cleaner or
alcohol, the lowest grade of Loctite, something like a Q-tip, compressed
air, and maybe some masking tape. Loctite comes in different grades and
usually has a note like "can be disassembled with hand tools" or "must
use power tools and/or heat to disassemble" on the package. You want
the "hand tools" kind, which _will_ come apart when you want it to.

Make su master off, battery disconnected. Unscrew the existing
screw. Apply brake cleaner or alcohol to Q-tip and clean ring terminal
on both sides; let it dry. Apply brake cleaner or alcohol to a fresh
Q-tip and clean the screw threads; let it dry. If there is any
possibility at all that you will get liquid into the generator/alternator,
cover the holes with masking tape. Then put brake cleaner or alcohol on
a fresh Q-tip and clean the place where the ring terminal bolts down -
get down in the threads if at all possible. Let it dry for a few minutes,
then give a gentle quick shot of compressed air in the threads to make
sure it's dry. Assemble the washer onto the new screw (rounded edge away
from screw head), then put the screw+washer through the ring terminal.
Hold the screw+washer+terminal near the place it screws into, and apply
the tiniest drop of Loctite that you can to the screw threads. (It may
be helpful to put a drop of Loctite on a cleaned piece of solid wire,
safety pin, etc, and then use that to put the Loctite on the threads,
instead of trying to squeeze the Loctite directly onto the threads.)
Start installing the screw, being very careful not to get any Loctite
anywhere other than on the threads. If you get Loctite on the ring
terminal or on the place where the ring terminal seats, take it apart,
clean everything, and start over. Once the screw is finger tight, get
the proper wrench or Allen key and torque it to spec. Remove any masking
tape that was applied and reconnect the battery. Count your tools. Do
a test run.

A: On the other hand, if the underside of the ring terminal is not totally
in contact with metal, then some of the electrical contact may be taking
place on the threads and Loctite may not be advisable. The best answer
in this case is probably to install an approved lockwasher under the
screw head (it should go screw, lockwasher, ring terminal, machine),
torque to spec, and inspect regularly.

Disclaimer: This is based on experience with ground vehicles and by
looking at the generator setup on a 182. I don't have an A&P; I don't
even have a TG&Y. Some of this may not be allowable owner maintenance.
Some of this may not be allowable on a certificated aircraft. Your
mileage may vary.

Matt Roberds

wrote:
I don't have an A&P; I don't
even have a TG&Y.

OK how many hear understand the TG&Y reference?

For extra points what did it stand for?

Gig 601XL Builder wrote:
I don't have an A&P; I don't
even have a TG&Y.

OK how many hear understand the TG&Y reference?

For extra points what did it stand for?

Wasn't TG&Y a discount store? I remember them from the 60s/70s.

John Galban=====N4BQ (PA28-180)

--
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