How To Turn an Electric Motor Into a VFD Motor

Electric motors are used for a number of different functions. Some functions require a constant speed. In these situations a constant speed motor is used. Other functions require a variable speed motor. There are two ways to get variable speed from a three-phase motor. The first way is to build the motor with additional field windings. This method is expensive and leads to purchasing larger motors. The other method is VFD or variable frequency drive. VFD can change a motor's speed or torque by changing the frequency or voltage of the power supplied to the motor. Installing a VFD can save you time, space and money.

Things You'll Need

• Variable frequency drive
• Screwdriver

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Instructions

1. • 1

     Shut off power to the electric motor at the main power panel. Disconnect the black, red and blue phase wires of the motor from the main power source.

   • 2

     Place the VFD between the motor and the power source. Connect the black, red, and blue wires of the power source to the L1, L2, and L3 terminals of the VFD. Tighten all terminal screws with the screwdriver.

   • 3

     Connect the black, red, and blue wires of the motor to the T1, T2, and T3 terminals of the VFD. Check the documentation of the VFD in case the manufacturer labeled the terminals differently. Turn the power back on at the main power panel and test the motor.