Hi Guys,

Can somebody please help me ?

I am busy fixing an electric motor cycle. ( one of these small jobs that fold up and fits into the boot of a car. )
This belongs to a friend of mine that stays in Toti and has recently been diagnosed with cancer. He wants to lug this thing along in his motor home and then to enable him to drive to the cafe or shop in the park.
Ok, to get back to the problem.......... It seems as though the control unit box that regulates the current to the drive motor has been fried. This unit controls other things like the flashers. hooter and light as well. All these functions work 100%. Just the motor part stopped working.
So I was thinking that if I fit a completely separate control box for the motor, that should solve the problem.
Here are the specs: 36 volt battery system with a 36 volt motor and peak current at 18 amp. Also shows 500 watt on the motor.
However what I have not seen before is the twist grip potentiometer. It has 3 wires running into the unit but does not use the conventional carbon slide and brass/copper trace like that of an older type radio.
This unit has a magnet connected to the twist grip and only moves between two metal stops very close to the back plate which I assume has some sort of coil or other gizimo imbedded in the bakelite back plate.
If need be and with a lot of effort I can change this to a conventional potentiometer but obviously would like to get the existing twist grip working.
Now.......can anybody help me with a circuit diagram that can a) use the existing pot or b) a diagram that can use a standard pot with an indication of the components and values needed.?