How do you wire a 4 wire cable from a generator l14-30r plug to an electric motor with 3 wires?

Answer 1

A L14-30R is a three pole four wire grounding 125/250 volt receptacle.

It is designed to supply voltage to a three wire system much like the connection to a range or clothes dryer.

The generator connections to the back of the receptacle are; blade hole with indent inwards is the ground.

Left (X) and right (Y) of the ground pin is the 240 volt output.

The last blade hole (W) is the neutral wire connection.

(X) to (W) will be 120 volts, (Y) to (W) will be 120 volts and (X) to (Y) will be 240 volts.

Check the nameplate of the motor to make sure that it is not three phase hence the three wires. Without more information about the motor a complete answer can not be given.

Answer 2

You can connect the ground wire from the generator cable to the motor's ground wire. For the two hot wires from the generator (X and Y), connect them to the two hot wires of the motor. The neutral wire from the generator can be capped off since the motor only requires two hot wires. Make sure to follow proper safety precautions and consult a professional if needed.