A three-phase motor should be wired with the positive and negative ends connecting to the corresponding power sources. The motor wires generally do not have symbols or colors that indicate the positivity or negativity of the wires, so the motor should be tested in a controlled environment before it is allowed to run.Continue Reading
Three-phase motors are available in three- and four-wire varieties. The three-wire motor is similar to the four-wire motor, but does not have a wire with the lowest voltage amount. The difference is that the fourth wire is simply not used and not connected to any power source. In a four-wire three-phase motor, all four wires are connected and the voltage ranges from low to high.
When wiring a three- or four-wire three-phase motor, it is important that the person doing the wiring takes extreme safety precautions. Failing to do so can result in injury or death. The motor as well as the person should be grounded. When testing the motor, the person should be prepared for the wiring to be wrong. The motor should only be turned on for less than 1 second to determine which way the wires run.Learn more about Engine