Hitachi SJ300 Series Inverter, GND, V W, P(+), N(–), Name, R S T, Motor, PD(+1), Function

2–5

SJ300 Inverter

Basic System Description

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

Breaker,

MCCB or

GFI

R S TPD(+1)

Inverter

		P(+)
		RB
R0
T0		N(–)
		GND
	U	V W

T1 T2 T3

Motor

Name	Function
Breaker / discon-	A molded-case circuit breaker (MCCB), ground
nect	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
AC Reactor	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 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 CE	This filter reduces the conducted noise in the
applications, see	power supply wiring between the inverter and
Appendix D)	the power distribution system. Connect it to the
	inverter primary (input side).
Radio noise filter	This capacitive filter reduces radiated noise from
(use in non-CE	the 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.
Braking resistor	Braking components are useful for increasing
	the inverter’s control torque for high duty-cycle
Braking unit
	(ON-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
	commercial 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.

Installation and Mounting Inverter

Thermal switch

NOTE: Some components are required for regulatory agency compliance (see Chapter 5 and Appendix D).