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Long cable motor recommendations.

 Long cable motor recommendations.

Product Line:
All Altivar drives
 Long cables to motor


Causes and Fixes

The main constraints with long motor cable are the high frequency earth current due to the stray capacitance and the motor overvoltage due to the reflection voltage waves phenomenon.

To reduce the stray capacitance earth current:
- do not use shielded cable. Metal conduits are preferable to shielded cable for long cable lengths if the environment must be protected against radiated interferences.
- reduce the switching frequency of the ATV.
- the sum of leakage current must be less than the tripping threshold, generaly 300mA.

You have to use motor choke oversized of one caliber or use two motor chokes in serial.

The ATV should be oversized about one caliber for several reasons:
- overcurrent due to earth leakage current (SCF or OCF default)
- loss of motor torque if the current limitation of the drive is reached.
- overheating of the ATV (OHF default)

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