Yaskawa E7L Drive Bypass - Manual (Page 194)

Diagnostic & Troubleshooting 6 - 22
If the Motor Overheats
Take the following steps if the motor overheats.
The load is too high.
If the motor load is too high and the motor is used when the effective torque exceeds the motor's rated torque, the motor will
overheat. Reduce the load amount by either reducing the load or increasing the acceleration/deceleration times. Also consider
increasing the motor size.
The ambient temperature is too high.
The motor rating is determined by a particular ambient operating temperature range. The motor will overheat if it is run con-
tinuously at the rated torque in an environment where the maximum ambient operating temperature rating is exceeded. Lower
the motor's ambient temperature to within its acceptable range.
The withstand voltage between the motor phases is insufficient.
When the motor is connected to the Drive output, Voltage surges are generated by standing waves that can occur with certain
combinations of Drive carrier frequency and motor cable length. Normally the maximum surge voltage is three times the Drive's
input power supply voltage (i.e., 1200VAC for a 480VAC). Be sure to use a motor with a withstand voltage between the motor
phases that is greater than the maximum surge voltage. In particular, when using a 480VAC Drive, use an inverter-duty (NEMA
MG1, Parts 30 & 31) motor. Motor protection filter can also be an effective measure.
If Peripheral Devices Like DDCs or Others are Influenced by Starting or Running
Drive
If noise is generated by Drive switching, implement the following countermeasures:
1. Change the Drive's Carrier Frequency Selection (C6-02) to lower the carrier frequency. This will help to reduce the amount
of internal switching.
2. Install an Input Noise Filter at the Drive's input power terminals.
3. Use metal conduit. Electric waves can be shielded by metal, so encase the Drive and power wires in metal.
4. Ground the Drive and motor.
5. Separate main circuit wiring from control wiring.