Hitachi NES1-002LB, Quick Reference Manual

Page: 43 / 295

Chapter 5 Wiring
5 - 8
・
In case of commercial power source switching functions,mechanical interlock the MC1 & MC2
contacts with each others is required.Otherwise you may damage the inverter and the danger of injury
and/or fire.Please refer to following diagram.
2)Inverter output terminals (U(T1), V(T2), and W(T3))
・
Use a cable thicker than the specified applicable cable for the wiring of output terminals to prevent the
output voltage between the inverter and motor dropping. Especially at low frequency output, a voltage
drop due to cable will cause the motor torque to decrease.
・
Do not connect a phase-advanced capacitor or surge absorber on the output side of the inverter. If
connected, the inverter may trip or the phase-advanced capacitor or surge absorber may be
damaged.
・ If the cable length between the inverter and motor exceeds 20 m (especially in the case of 400 V
class models), the stray capacitance and inductance of the cable may cause a surge voltage at motor
terminals, resulting in a motor burnout. A special filter to suppress the surge voltage is available. If
you need this filter, contact your supplier or local Hitachi Distributor.
・ When connecting multiple motors to the inverter, connect a thermal relay to the inverter output circuit
for each motor.
・
The RC rating of the thermal relay must be 1.1 times as high as the rated current of the motor. The
thermal relay may go off too early, depending on the cable length. If this occurs, connect an AC
reactor to the output of the inverter.
3)DC reactor connection terminals (PD(+1) and P(+))
・
Use these terminals to connect the optional DC power factor reactor (DCL).
As the factory setting, terminals P(+) and PD(+1) are connected by a jumper.
Remove this to connect the DCL.
・
The cable length between the inverter and DCL must be 5 m or less.
Remove the jumper only when connecting the DCL.
If the jumper is removed and the DCL is not connected, power is not supplied to the main circuit of
the inverter, and the inverter cannot operate.
4)Inverter ground terminal (G )
・ Be sure to ground the inverter and motor to prevent electric shock.
・ According to the Electric Apparatus Engineering Regulations, connect 200 V class models to
grounding electrodes constructed in compliance with type-D grounding (conventional type-III
grounding with ground resistance of 100
Ω or less) or the 400 V class models to grounding electrodes
constructed in compliance with type-C grounding (conventional special type-III grounding with ground
resistance of 10
Ω or less).
・
Use a grounding cable thicker than the specified applicable cable, and make the ground wiring as
short as possible.
・ When grounding multiple inverters, avoid a multi-drop connection of the grounding route and
formation of a ground loop, otherwise the inverter may malfunction.
Power
source
R/L1 U
S Inveter V
T/N W
Motor
ELB
MC0
MC1
MC2
Inverter
Inverter
Inverter
Grounding bolt
prepared by user
Inverter
Inverter
Inverter