Omron VS mini J7 User Manual page 36

Wiring
Countermeasures against
Induction Noise
Power supply
Countermeasures against
Radio Interference
Power supply
Cable Length between
Inverter and Motor
22
As described previously, a Noise Filter can be used to prevent induction noise
from being generated on the output side. Alternatively, cables can be routed
through a grounded metal pipe to prevent induction noise. Keeping the metal
pipe at least 30 cm away from the signal line considerably reduces induction
noise.
MCCB
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.
The cable between the Inverter and the motor should be as short as possible.
MCCB
Noise
Filter
As the cable length between the Inverter and the motor is increased, the
floating capacity between the Inverter outputs and the ground is increased
proportionally. The increase in floating capacity at the Inverter outputs causes
the high-frequency leakage current to increase, and this may adversely affect
peripheral devices and the current detector in the Inverter's output section. To
prevent this from occurring, use a cable of no more than 100 meters between
the Inverter and the motor. If the cable must be longer than 100 meters, take
measures to reduce the floating capacity by not wiring in metallic ducts, by
using separate cables for each phase, etc.
Also, adjust the carrier frequency (set in n46) according to the cable length
between the Inverter and the motor, as shown in the following table.
Cable length
Carrier frequency 10 kHz max.
Note Single-phase motors cannot be used.
The Inverter is not suited for the variable speed control of single-phase
motors.
The rotation direction of a single-phase motor is determined by the capacitor
starting method or phase-splitting starting method to be applied when starting
the motor.
In the capacitor starting method, however, the capacitor may be damaged by
a sudden electric discharge of the capacitor caused by the output of the
Inverter. On the other hand, the starting coil may burn in the phase-splitting
starting method because the centrifugal switch does not operate.
Metal pipe
CIMR-J7AZ
VARISPEED
Signal line
Steel box
CIMR-J7AZ
Noise
VARISPEED
Filter
50 m or less 100 m or less
5 kHz max.
Chapter 2-2
30 cm min.
Controller
Metal pipe
More than 100 m
2.5 kHz