Have had a 1960 PA23-250 for almost 10 years now, love it. Two years
ago switched from the generators to the InterAv alternator kit. Feel
it was the right decision and am pleased with the results.
Reasons for switch:
1) Generators do NOT put out any charging current below a certain RPM,
in our case it took 1700 RPM to get any appreciable output, they were
calling us the AzJet because we were blowing over the 172s behind us in
order to keep the battery up.
2) My partner called me several times to come jump start the plane, he
would forget to turn off all unneeded lights and radios while taxiing
back and the battery would run down.
3) Went through the trouble about 5 years ago to get the generators
overhauled, new regulators and balancing relay, still had balance and
charging problems.
After the conversion:
1) alternators put out good current at idle, radios operate just fine
with engines idling.
2) End of dead battery problems, no more dead battery when opening up
the plane.
3) I can taxi around without blowing the 172s all over the place.
4) So far (find some wood) have not had a balancing or charging
problem.
5) Generator whine (feedback through intercom) is gone, radio sound is
noticeably cleaner.
Notes to pay attention to:
1) make sure the black ring (the diode holder) on the back of the
alternator does not contact anything, has plenty of clearance around
it, else it grounds out through the diode holder and will burn out the
alternator.
2) Use the old regulator mount on the aft side of the firewall to mount
the new regulator assembly to, stays cooler and cleaner, much neater
wiring installation.
3) Absolutely replace the output wires with a #4 guage wire up to the
fuselage juction block.
4) Use a #4 guage wire to fabricate the ground bonding wire, make
absolutely sure the bonding straps on each side of the engine case to
the engine mounts are clean and in good condition.
5) Add an additional ground wire from the regulator to the alternator
(solved a balance problem).
6) weigh and track all parts coming off and going on, including wires
pulled and installed for form 337 weight and balance changes. (Hint:
weigh the wire spool before and after you run it, in order to get
accurate weight of what was installed.)
I am an A&P in the D.C area, my I.A. and Balto FSDO were watching
over my shoulders, the more meticulous I was, the happier FSDO got, and
signed off the 337 on the spot.

Good Luck


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AztecN867DC
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