3-18
The cable between the Inverter and the motor should be as short as possible.
3G3EV
Power supply
Steel box
Noise
filter
Noise
filter
Metal pipe
D Cable Length between Inverter and Motor
As the cable length between the Inverter and the motor is increased, the floating capac-
ity between the Inverter outputs and the ground is increased proportionally. The in-
crease 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 n37) according to the cable length between the
Inverter and the motor, as shown in the following table.
Cable length between Inverter and motor 50 m max. 100 m max.
Carrier frequency (n37) 10 kHz max. (1, 2, 3, 4) 5 kHz max. (1, 2)
D 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 cen-
trifugal switch does not operate.
Design Chapter 3
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