Basic System Description - Hitachi SJ100 Series Instruction Manual

Basic System Description

A motor control system will obviously include a motor and inverter, as well as fuses for
safety. If you are connecting a motor to the inverter on a test bench just to get started,
that's all you may need for now. But a system can also have a variety of additional
components. Some can be for noise suppression, while others may enhance the inverter's
braking performance. The figure and table below show a system with all the optional
components you may need in your finished application.
From power supply
L1 L2
L3
+1
+
Inverter
RB
GND
T1
T2 T3
Motor
Thermal switch
Name
Fuse
Cut-off
Input-side
switch
AC Reactor
Radio noise filter Electrical noise interference may occur on
EMI filter (for
CE applications)
Radio noise filter
(use in non-CE
applications)
DC link choke
Braking resistor
Radio noise filter Electrical noise interference may occur on
AC reactor
LCR filter
Note that some components are required for regulatory
agency compliance (see Chapter 5).
SJ100 Inverter
Function
Current overload protection for power
supply and wiring.
This is useful in suppressing harmonics
induced on the power supply lines, or when
the main power voltage imbalance exceeds
3% (and power source capacity is more
than 500 kVA), or to smooth out line fluctu-
ations. It also improves the power factor.
nearby equipment such as a radio receiver.
This magnetic choke filter helps reduce
radiated noise (can also be used on output).
Reduces the conducted noise on the power
supply wiring generated by the main power
supply to protect the inverter. Connect to
the inverter primary (input side).
This capacitive filter reduces radiated noise
from the main power wires in the inverter
input side.
Suppresses harmonics generated by the
inverter. However, it will not protect the
input diodes.
This is useful for increasing the inverter's
control torque for high duty-cycle (on-off)
applications, and improving the decelerat-
ing capability.
nearby equipment such as a radio receiver.
This magnetic choke filter helps reduce
radiated noise (can also be used on input).
This reactor reduces the vibrations in the
motor caused by the inverter's switching
waveforms, by smoothing the waveforms to
approximate commercial power quality. It
is also useful when wiring from the inverter
to the motor is more than 10m in length, to
reduce harmonics.
Sine wave shaping filter for output side.
2–5