TR2/3/3A TR3 Ground conversion question

[RedTR3]

I am going to be converting my TR3 from positive to negative ground. I have the instructions from the VTR link and everything looks real simple. My question is, why is the starter not affected by the conversion? Seems like if it is a DC motor its rotation is affected by polarity. I know the answer must be simple but I am just a purely mechanical guy and do not know all the electrical mysteries in my LBC... Thanks, Tim

 

[startech47]

It is not a permanent magnetic motor. The field coils and the armature are both energised by the battery, thus if you reverse the from of current, than both change at the same time and the motor rotates the same direction. EE's correct me on the current flow thing, is it the current or the electrons that flow. Phil

 

[Keoke]

Either one just stick to one or the other don't mix em up.----Keoke- /ubbthreads/images/graemlins/laugh.gif

 

[martx-5]

I work for an automotive electrical remanufacturer, and we do a fair amount of marine starters where the starter has to spin one of the engines in a CCW direction in a twin screw application. The way to do this in a starter is to either rewind the fields in the opposite direction, or rewind the armature in the opposite direction. That is the only way to get it to go the other way. If you change polarity, you're changing it in both the fields and the armature, so the net result is that it will spin in the same direction. All the Delco opposite marine applications that I've seen have changed the direction of the field windings. Ford used both field and armature winding differences, so you can take a set of Ford opposite fields and mate them with an opposite rotation armature, and the starter will spin in the normal direction. By the way, I've ignored all the stuff concerning the armature shafts and drives, as with reverse rotation, they are also different.

 

[Geo Hahn]

Same deal with the wiper motor... but you will want to swap the 2 wires on the ammeter and reverse the coil connections (assuming they were correct before).

If your TR3 has an aftermarket electric fan that will run backwards I think so the wires to it would also need to be swapped.