By Alexis Rohlin Updated Mar 24, 2022

Polka Dot Images/Polka Dot/Getty Images

A three‑phase motor transforms alternating current from three power conductors into mechanical motion. The supply creates a rotating magnetic field that drives the stator and turns the shaft. Correct phase sequence is essential; a reversed sequence can spin the motor incorrectly and cause damage.

Step 1

Select the phase‑rotation (or phase‑sequence) mode on your multimeter.

Step 2

Locate the motor’s terminal block and identify the three connections labeled L1, L2, and L3. Connect the multimeter leads to the corresponding terminals on the power supply.

Step 3

Observe the meter’s display. A reading of "OK" confirms the correct phase order. An "ER" (error) indicates that the power feed is reversed, which would make the motor rotate in the wrong direction.

Step 4

If the meter shows "ER", first shut off the motor and disconnect the power. Swap the positions of any two phase wires, re‑attach the leads, and power the unit again. The meter should now display "OK," proving that the motor will run in the intended direction.