Hitachi WJ Series

Chapter 5 Wire Connection
5-2-4
■ Cautions for inverter output terminals
DANGER
Fire
● Risk of fire, malfunction and damage to machine!
Do
 Use wires with a thickness equal to or above the applicable wire.
Otherwise, the output voltage may drop between the inverter and the motor.
Especially at low speed output, voltage drop caused by wiring reduces the
torque of the motor.
Failure
● Risk of damage to the inverter!
Prohibited
 Do not install a phase advance capacitor or surge absorber, as they may cause
inverter errors or damage to the capacitor or surge absorber.
Burnout
● Risk of burnout of the motor!
Do
 When connecting multiple motors, install thermal relays for each of them.
Burnout
● Risk of burnout of the motor!
Do
 If the wire length exceeds 20 m, due to the stray capacitance or the
inductance of the wire, surge voltage may be generated on the motor terminals
(especially on 400 V class), which may cause the motor to burnout.
 For suppressing surge voltage filter, please contact your supplier or local
Hitachi sales office.
Burnout
● Risk of burnout of the motor!
Do
 The RC value of the thermal relay should be 1.1 times the rated current of the
motor. The thermal relay may trip earlier than intended depending on the wire
length. In that case, install an AC reactor on the output side of the inverter.