Charging system Problems

[Greg Bockelman]

I need electrical system help. My generator and regulator have been bench tested and work as designed. But the juice is not getting back to the battery. The wiring is new so that should not be an issue. My amp guage will show a discharge with nav lights on and zero with them off. This is the only draw on the system other than the starter.

I am not well enough versed in how the electrical system works to be able to trouble shoot it. And the mechanic I have working on it isn't much better. Any ideas?

Also, what is the proper way to flash the field on the regulator?

[GLB]

Re: Charging system Problems

Hi to flash the field you use a jumper wire on the battery terminal of the regulator to the Field terminal, to polarize the system you need a heavy gage (like a solid # 12 / 14 copper wire) and go from the battery terminal to the armature terminal on the voltage regulator. If that doesn't do it check for a burnt generator fuse or bad circuit breaker.
PS: when doing either it is just very short contact, maybe a bit longer when polarizing.
GB

[Hank Jarrett]

Re: Charging system Problems

I doubt this is your problem but while you are checking your system there is a common problem with most charging systems I have seen. The voltage regulator on a charging system is designed to adjust the charge voltage with changing temperatures. Lead Acid batteries take higher voltages as the temperature rises and the voltage regulator has to account for that. I'll NEVER understand why so many planes have the voltage regulator on the HOT side of the firewall and the battery in the fuselage where it's cool. The regulator will raise the voltage for the hotter battery (which is behind your seat and as cool as you are). That's why so many aircraft charging systems boil batteries to death. If you are working your whole system put the voltage regulator as close to the battery as you can so it can do it's job and keep the voltage correct for the temperature of the battery.
Hank

[Ragwing nut]

Re: Charging system Problems

Check the position of the master switch. Make sure you have it in the correct position since it is a 2 position switch. I don't remember if the first or second notch was bat and alt/gen

Mike

[perryv1]

Re: Charging system Problems

If the power to the voltage regulator is connected to the Battery side of the Ammeter,it will only show how much current is being drawn from the system ie lights and acc. but will not show how much the charging system is contributing to the state of system voltage.Make sure the only thing on the battery side of the ammeter is the battery
Good luck
Perryv

[jdoran]

Re: Charging system Problems

Here's a test you can do.

With the engine running, short the field (F) terminal to ground. This very short term connection should indicate maximum output on the ammeter.

If it does, the regulator is bad, the generator is good.

The studs on most generators are labeled B for battery (usually the larger post, and F for thew field stud.