The International Cessna^® 170 Association

I have a Jasco alternator (Model 656OT) that seems to charge intermittently, that is from time to time the ammeter will show a discharge for periods of several minutes and then go back to charging. This seems to happen regardless of engine speed and I have tried just about everything I can think of to resolve the problem. The voltage regulator has been replaced, all wiring and circuit breakers checked, replaced the battery but the problem persists. The alternator has done only approximately 300hrs since new. Any ideas?

Circuit breaker has lost it's continuity/dirty contacts/calibration.... or intermittent c.b./fuse/fuse--holder.
<also>
Keep in mind your cockpit Master Switch has TWO CIRCUITS in it.
ONE... completes a GROUND to activate your battery relay. The SECOND completes the charging circuit for your gen/alt. (usually to the regulator).

I once experienced the same problem with my generator charging circuit. The gen would occasionally not charge and then would resume charging. When I pulled gently on the cockpit Master Switch (my '53 model has push/pull switches in the panel) the pulling action re-connected the charge circuit inside the switch.

I disassembled the switch, cleaned the contacts, lubricated with dielectric grease (Dow Corning DC-4 silicone grease) and it's now worked flawlessly for an additional 10 years.

Hope that helps.

The 60 Amp Alt will over charge the battery and the electronic voltage regulator will then shut down the alternator until the battery discharges to the control voltage. there is a adjustment screw to control this on the regulator.

lower the voltage and this symptom will stop.