Hitachi SJ300-037HFE Inverter, GND, Name, P(+), N(–), 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

Name

Function

Breaker / discon-

A molded-case circuit breaker (MCCB), ground

Breaker,

nect

fault interrupter breaker (GFI), or a fused

MCCB or

disconnect device. NOTE: The installer must

GFI

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

R

S

T

inverter primary (input side).

PD(+1)

Radio noise filter

This capacitive filter reduces radiated noise from

Inverter

(use in non-CE

the main power wires in the inverter input side.

P(+)

applications)

DC link choke

The choke suppresses harmonics generated by

the inverter. However, it will not protect the

RB

input diode bridge rectifier.

R0

Braking resistor

Braking components are useful for increasing

T0

N(–)

the inverter’s control torque for high duty-cycle

Braking unit

(ON-OFF) applications, and improving the

GND

decelerating capability.

U

V

W

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

T1

T2

T3

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.

Motor

Installation and Mounting Inverter

Thermal switch

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