Hitachi SJ Series, User Manual

Page: 74 / 786

7-19
Chapter 7
Wire Connection and Optional Devices
7.5.9 Outline of Applicable Peripheral
Devices
Total wiring length Sensitive current (mA)
100m or shorter 50
300m or shorter 100
No. Name Function
<1> Wire See page 7-9 Recommended Wire Diameter, Wiring Tools,
and Crimping Terminals.
<2> Earth-leakage breaker (ELB)
<3> Magnetic contactor (MC)
<4> Input side reactor
(for harmonic suppression,
power coordination, and
improvement of power
factor)(ALI-
)
This is applied as a countermeasure against harmonic
suppression, or when imbalance of power supply voltage is
3% or above, or when power supply capacity is 500kVA or
above. It is also used when a rapid change is made to power
supply voltage. It is also effective in improving power factor.
<5> Inverter noise filter (NF- ) This reduces the conductive noise that is generated from the
inverter and transferred to the wire. Connect to the primary
side (input side) of inverter.
<6> Radio noise filter (zero-phase
reactor) (ZCL- ) When the inverter is used, noise may be generated on an
adjacent radio or other devices through wiring on the power
supply side. This is used for reducing the noise (reducing
radiation noise).
<7> Input-side radio noise filter
(capacitor filter) (CFI- ) This reduces the radiation noise that is emitted from the wire
on the input side.
<8> DC reactor (DCL- - ) This suppresses harmonics generated from the inverter.
<9> Braking resistor This is used for increasing the braking torque of inverter,
repeating power on and off at high interval, or reducing the
speed of high load caused by moment of inertia.
<10> Regenerative braking unit
(BRD-
)
<11> Output-side noise filter
(ACF-C ) This is installed between the inverter and motor to reduce the
radiation noise that is emitted from the wire. It is used to
reduce radio interference on radios or televisions or prevent
malfunctioning of measurement instruments and sensors.
<12> Radio noise filter (zero-phase
reactor) (ZCL-
)
This is applied for reducing noise generated on the output side
of inverter. (It can be used on both the input side and output
side.)
<13> Output-side AC reactor
(ACL- -
)
for reducing
vibration/preventing
malfunctioning of thermal
relay
When a general-use motor is driven by the inverter, compared
with when it is run by commercial power supply, larger
vibration may be generated. By connecting this device
between the inverter and motor, you can reduce the vibration
of motor. Also, if the wiring length between the inverter and
motor is long (10m or longer), by inserting a reactor, you can
prevent malfunctioning of the thermal relay caused by
harmonic attributable to switching of inverter. You can also use
a current sensor instead of the thermal relay.
<14> LCR filter This is a filter installed between the inverter and motor. It
improves output current and voltage waveform to reduce
motor vibration, noise, and radiation noise emitted from the
wire to convert output-side waveform to sine wave. It is also
effective in suppressing surge voltage.
R S T
R0
T0
Power supply
U V W
PD
P
N
Motor
M
RB
<1>
<2>
<3>
INV
<4>
<5>
<6>
<7>
<8>
<9>
<10>
<11>
<12>
<13>
<14>
Cautions
・
The applicable devices shown in this chapter are those when Hitachi standard 3-phase 4-pole
cage motor is used.
・
For the circuit breaker, choose an appropriate device by taking breaking capacity into
consideration.
(Use an inverter-compatible model.)
・
To ensure safety, use an earth-leakage breaker (ELB).
・
Use a 75°C copper wire (HIV wire).
・
If the wiring length exceeds 20m, a thick power line needs to be used.
・
Use an alarm output contact of 0.75 mm
2
.
・
Tighten the terminal screws at a specified torque. If they are not tightened enough, it may cause
short circuit or fire. If they are tightened too much, it may damage the terminal block or inverter.
・
Employ different sensitive currents for earth-leakage breaker (ELB) depending on the total
wiring length between the inverter and power supply and between the inverter and motor.
Also,
use a time-delay type earth-leakage breaker. High-speed type products may malfunction.
・
If wiring is performed on a metal tube using CV wire, leak current is about 30mA/km.
・
As relative permitivity of IV wire is high, the current increases by about 8 times. Therefore, use
an item with 8 times sensitive current that is shown on the table below. If the total wiring length
exceeds 100m, use a CV wire.