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Note:
1. It is appropriate to use the recommended cable size under 40ºC and rated current. The wiring distance
between the inverter and the motor should be no more than 50 m without using any filter and between
50~100m using chokes. It is possible to have longer distances if a sine wave filter is installed.
2. Terminals P1, (+), PB and (-) can be used to connect an optional DC reactor.
C.4.3 Routing the cables
Route the motor cable away from other cable routes. Motor cables of several drives can be run in parallel
installed next to each other. It is recommended that the motor cable, input power cable and control cables are
installed on separate trays. Avoid long parallel runs of motor cables with other cables to decrease
electromagnetic interference caused by the rapid changes in the drive output voltage.
Where control cables must cross power cables make sure that they are arranged at an angle as near to 90
degrees as possible.
The cable trays must have good electrical bonding to each other and to the grounding electrodes. Aluminum
tray systems can be used to improve local equalizing of potential.
A figure of the cable routing is shown below.
C.4.4 Checking the insulation
Check the insulation of the motor and motor cable as follows:
1. Check that the motor cable is connected to the motor and disconnected from the drive output terminals U,
V and W.
2. Measure the insulation resistance between each phase conductor and the Protective Earth conductor
using a measuring voltage of 500 Vdc. For the insulation resistance of other motors, please consult the
manufacturer's instructions.
Note: Moisture inside the motor casing will reduce the insulation resistance. If moisture is suspected, dry the
motor and repeat the measurement.
C.5 Breaker, electromagnetic contactor and leakage protection switch
Due to the inverter output high frequency PWM voltage waveform, the existance of distributed capacitance between
IGBT and heatsink in internal inverter, and the distributed capacitance between motor stator and rotor, they will cause
the inverter inevitably generate high-frequency leakage current to ground. The high-frequency leakage current will
back flow to grid through the earth to interference the leakage protection switch, thus causing the leakage protection
switch malfunction. This is due to the inverter output voltage characteristics inherent in the decision.
To ensure the stability of the system, it is recommended to use an inverter dedicated leakage protection switch
whith rated residual operation current of 30mA or more (for example, corresponds to IEC60755 Type B). If you
are not using the inverter dedicated leakage protection switch, and you have malfunction, try to reduce the
carrier frequency, or replace the electromagnetic leakage protection switch for one of 300mA or more.
It is appropriate to use a circuit breaker (MCCB) to avoid overload and which complies with the inverter power
in the 3-phase AC power input (terminals R, S and T). The capacity of the circuit breaker should be 1.5-2 times
of the rated current.
136 - 144
Peripheral Options and Parts Appendix C
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