Basic System Description - Hitachi SJ7002 Series Instruction Manual

Basic System Description

Breaker,
MCCB or
GFI
Inverter
R0
T0
T1
Thermal switch
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A motor control system will obviously include a motor and inverter, as well as a breaker or
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 perfor-
mance. The figure and table below show a system with all the optional components you may
need in your finished application.
Power source
L1 L2 L3
R S T
PD(+1)
P(+)
RB
N(–)
GND
U V W
T2 T3
Motor
NOTE: Some components are required for regulatory agency compliance (see Chapter 5 and
Appendix D).
Name
Breaker / A molded-case circuit breaker (MCCB), ground
disconnect fault interrupter breaker (GFI), or a fused disconnect
device. NOTE: The installer must refer to the NEC
and local codes to ensure safety and compliance.
Input side This is useful in suppressing harmonics induced on
AC Reactor 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 fluctuations. It also improves the power factor.
Radio noise filter Electrical noise interference may occur on nearby
equipment such as a radio receiver. This magnetic
choke filter helps reduce radiated noise (can also be
used on output).
EMI filter (for This filter reduces the conducted noise in the power
supply wiring between the inverter and the power
CE applications,
see Appendix D) distribution system. Connect it to the inverter
primary (input side).
Radio noise filter This capacitive filter reduces radiated noise from the
(use in non-CE main power wires in the inverter input side.
applications)
DC link choke The choke suppresses harmonics generated by the
inverter. However, it will not protect the input diode
bridge rectifier. A DCL reactor is required for
models -185xxx to -4000xxx
Braking resistor Braking components are useful for increasing the
inverter's control torque for high duty-cycle (ON-
Braking unit
OFF) applications, and improving the decelerating
capability.
Radio noise filter Electrical noise interference may occur on nearby
equipment such as a radio receiver. This magnetic
choke filter helps reduce radiated noise (can also be
used at input).
Output side This reactor reduces the vibrations in the motor
AC reactor caused by the inverter's switching waveform, by
smoothing the waveform to approximate commer-
cial power quality. It is also useful to reduce
harmonics when wiring from the inverter to the
motor is more than 10m in length.
LCR filter Sine wave shaping filter for output side. The LCR
filter is not required for models -1850xxx to -
4000xxx.
SJ700 Inverter
2
Function
2–5