Re: 1934 1101 coil problems, HELP!

Posted by HH56 On 2021/8/16 9:06:15

As Dave said, the coil should be seeing exactly what the battery is seeing and allowing for wire runs and some possible loss at switches or connections, maybe a tenth less. With the engine off coil would be supplied with the standing battery voltage of 6.3v and with engine running it would see what the generator is providing. On later cars with a voltage regulator this would be adjusted to provide a maximum of around 7.0-7.4 volts.

From what I remember about third brush generators (not very much) with only a cutout relay, they have no voltage regulation and voltage output is kept in check by the battery and connections to it. With the battery keeping the voltage in check, the brush adjustment mostly changes current output and is adjusted for the output to be in the range of 18-20 amps (per the 10th and 11th series specs) which will be enough going to the battery that it will be kept charged when head lights are on.

If you are seeing 10-11 volts I would really wonder about the battery or the condition of some of the connections and would also think any light bulbs in the car would be very vulnerable. There are a few stories on the forum from people who had accidentally disconnected the batteries while the car was running and lights were on. Sad result was their expensive head light bulbs blew because of the sudden voltage surge out of the generator when it lost whatever regulation the battery was providing.