I was disassembling a belt disc sander today and noticed that there was a rather large relay between the switch and the motor. The relay consists mostly of a large copper coil. The motor doesn't have a capacitor and neither does the switch assembly. There are three wires coming out of the motor: red, white and black. All of the wires are of the same size about 14AWG.
When I tried wiring the motor without the relay, I couldn't get it to start without turning the shaft by hand. This would mean that the relay was acting as a starter. I am perplexed because I was under the impression that the only way to start a motor was either by hand or a start capacitor.
Can a relay be used to start a motor, if so, how?