Polarity

[Pappabob]

Does anyone know of any reason why a Model A motor on a run stand can't be wired like most other engines (negative ground) ???
Reason: Not sure if a tach will work if wired "positive ground"??

Check out "Dearborn Granny" one YouTube. ;o)

 

[Patrick L.]

It doesn't care, it'll work either way if wired correctly.

 

[nkaminar]

The starter motor will work with either polarity. The coil must be wired correctly, negative to negative and positive to positive. Some coils will say BAT and DIST or something like that. These coils are for modern cars which have a negative ground. So the BAT side should be hooked to the positive side of the battery an the DIST side run to the distributor. If in doubt whether you have it hooked up correctly, check with a volt meter.

 

[Badpuppy]

The generator, if installed, will need to be repolarized as well.

 

[Pappabob]

Thanks for the input. I'll give it a try with the negative ground paying attention to make sure the starter is turning the correct direction. About to begin the wiring today. ;o)

 

[Herb Concord Ca]

Started will turn the correct direction. It doesn’t care about polarity.