Design
Chapter 3
D Do Not Use an Electromagnetic Switch
Do not connect an electromagnetic switch or magnetic contactor to the output circuit. If a load is con-
nected to the Inverter during operation, an inrush current will actuate the overcurrent protective circuit in
the Inverter.
D Installing a Thermal Relay
This Inverter has an electronic thermal protection function to protect the motor from overheating. If,
however, more than one motor is operated with one Inverter or a multipolar motor is used, always install
a thermal relay (THR) between the Inverter and the motor and set to “0.0” (no thermal protection) for
constant No. 31 (“THR” indicator).
In this case, program the sequence so that the magnetic contactor on the input side of the main circuit is
turned off by the contact of the thermal relay.
D Installing a Noise Filter on the Output Side
Connect a Noise Filter to the output side of the Inverter to reduce radio noise and induction noise.
3G3EV
3G3IV-PLF
Noise Filter
Power supply
Induction noise
Radio noise
Signal line
Controller
AM radio
Induction Noise:
Radio Noise:
Electromagnetic induction generates noise on the signal line, causing the control-
ler to malfunction.
Electromagnetic waves from the Inverter and cables cause the broadcasting radio
receiver to make noise.
D How to Prevent Radio Noise
Radio noise is generated from the Inverter as well as the input and output lines. To reduce radio noise,
install Noise Filters on both input and output sides, and also install the Inverter in a totally enclosed steel
box.
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OMRON [ OMRON ELECTRONICS LLC ]
