model T with distributor
 

Is it normal to see the ammeter discharge when the points close on the Model T with a distributor? It seems very perplexing

Re: model T with distributor
 

Yes would be normal. You would see the same thing on most any car with points, it's just like closing a switch.

Re: model T with distributor
 

When the points close, the coil draws current to build the magnetic field and it does this until the points open again. Its normal to see the amp meter fluctuate during the start phase until the engine fires up and rpm builds. At that point the breaker is opening and closing too fast for the amp meter to keep up plus the generator comes on line so it settles back down to more of a steady state.

Re: model T with distributor
 

It's a dead short so yes.

Re: model T with distributor
 

A dead short is a circuit with no load but the conductor wire. A dead short would burn the wire or blow the fuse if there is one. An energized coil is an electromagnet until the points open back up.

Re: model T with distributor
 

Thanks for all your explanations. We had the unlucky occurrence of searching for a short and realized it was the closed points.

Re: model T with distributor
 

Back in the day when guys would sit with their girlfriends by the lake to watch submarine races they’d turn the ignition switch on and jab the starter button until the ammeter set straight up in the middle indicating the points were open.
Then they could turn the radio on and sit and listen to it without the ignition killing the battery.
That was before cars had an accessory position on the ignition switch.
You can also check to see if your stop lights are working from the driver’s seat.
When you push the brake pedal the ammeter should show about 2 or 3 amps discharge.