Hitachi L2002 Inverter Output to the Motor

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Introduction to Variable-Frequency Drives

Getting Started

Inverter Output to the Motor

The AC motor must be connected only to the inverter’s	3-Phase AC Motor
output terminals. The output terminals are uniquely
labeled (to differentiate them from the input terminals)	U/T1	V/T2
with the designations U/T1, V/T2, and W/T3. This
corresponds to typical motor lead connection designa-
tions T1, T2, and T3. It is often not necessary to connect			Earth
a particular inverter output to a particular motor lead for
a new application. The consequence of swapping any	W/T3		GND
two of the three connections is the reversal of the motor
direction. In applications where reversed rotation could

cause equipment damage or personnel injury, be sure to verify direction of rotation before attempting full-speed operation. For safety to personnel, you must connect the motor chassis ground to the ground connection at the bottom of the inverter housing.

Notice the three connections to the motor do not include one marked “Neutral” or “Return.” The motor represents a balanced “Y” impedance to the inverter, so there is no need for a separate return. In other words, each of the three “Hot” connections serves also as a return for the other connections, because of their phase relationship.

The Hitachi inverter is a rugged and reliable device. The intention is for the inverter to assume the role of controlling power to the motor during all normal operations. There- fore, this manual instructs you not to switch off power to the inverter while the motor is running (unless it is an emergency stop). Also, do not install or use disconnect switches in the wiring from the inverter to the motor (except thermal disconnect). Of course, safety-related devices such as fuses must be in the design to break power during a malfunction, as required by NEC and local codes.