To reverse the rotation of a three-phase motor, which lead changes are specified?

• A. L1 to T2 and L2 to T1
• B. L1 to T3 and L3 to T1
• C. L2 to T3 and L3 to T2
• D. L1 to T1 and L3 to T3

Answer: (B)

The direction of rotation in a three‑phase motor is determined by the order in which the windings are energized—the phase sequence. To reverse that sequence, you swap two of the supply leads to two windings, which changes the phase order from ABC to ACB and makes the rotating magnetic field turn the other way.

A correct way to do this is to reconnect so that the supply line that originally fed one winding now feeds the winding that was fed by a different line, and vice versa for a second winding, while the third remains on its original terminal. For example, connect L1 to the terminal that was formerly fed by L3 (T3) and connect L3 to the terminal that was formerly fed by L1 (T1), with L2 staying on T2. This accomplishes the swap of two lines and reverses the rotation.

In essence, any interchange of two of the three input lines to the motor windings will reverse rotation, and the pictured lead change is one standard way to achieve that.