For three-phase induction motors, the windings are connected in either a Wye or a Delta configuration. Typically the motor has three, six, nine or twelve external leads, depending on what the motor was designed for. In a three-lead motor, only three terminal leads are brought out of the motor. This motor is designed to work on a single voltage. Its leads are designated T1, T2, T3 and the windings of this motor may be Wye or Delta-connected inside. 

 

Whether it is Wye or Delta-connected is usually of no importance to the electrician. We are just responsible for ensuring that the supply voltage is suitable for the rated voltage on the nameplate. The motor is usually connected L1 to T1, L2 to T2, and L3 to T3. If you wish to have the motor rotate in the opposite direction, we are required to just inter-change any two line leads. 

 

However, if there are more than three leads coming out of the motor, the motor will most likely function on more than one supply voltage. The following article will walk you through the standard terminal designations for each type of motor, and how to properly wire up this multi-functional three-phase motor.