How to make a powerful motor from a car generator

Somehow I got an old but working generator. I decided to convert it into a BLDC motor. In the future I will use it for a homemade electric bicycle or electric scooter. In general, the motor is suitable wherever a variable electric drive is required.

Materials used

• car generator;
  
• solder;
  
• copper wires;
  
• battery;
  
• control board with speed controller.

Tool: ratchet with extension and set of sockets; screwdrivers; hammer; narrow nose pliers; bearing puller; wire cutters; stationery knife; soldering iron

The process of converting a generator into a BLDC engine

We take the car generator and begin to disassemble it.

First of all, unscrew the nuts that hold the back cover with the bearing.

Remove the brush assembly.

Unscrew the pulley mount and remove it.

We take out the key.

Remove the front cover of the generator.

We take out the rotor.

We unscrew the fastenings of the stator winding leads from the rectifier diode block.

Disconnect the stator from the back cover.

Unscrew the fastenings of the diode bridge and remove it.

We clear the conclusions. We connect the stator winding according to the "triangle" diagram.

Solder the wires to the terminals.

Take the removed brush assembly. Its design includes a voltage regulator. It needs to be disconnected.

We solder the wires to the brushes, bypassing the voltage regulator.

Reassemble the engine in reverse order. If necessary, we change the bearings and grind the slip rings.

We connect the rotor winding to the power supply. The stator outputs are connected to the control board. The driver itself is powered from the battery.

Using a regulator, which can be a regular potentiometer, we adjust the speed of the BLDC motor.

Useful tips

The BLDC motor obtained in this way has insufficiently good efficiency, since energy is spent in the field winding to bias the rotor. This drawback can be eliminated by installing neodymium magnets.
I took a driver that works without a Hall sensor. It's cheaper and quite suitable. If you want to get good performance, you can put a Hall sensor in the motor and connect it to the appropriate board.
Before connecting the motor to the battery, be sure to check the windings for interturn short circuit and breakdown to the housing.

Watch the video