Electrical Installation
3
3.10 Dynamic Braking Option, Motor Protection
YASKAWA SIEPYEULA5001C LA500 Technical Manual 69
■ Length of the Motor Cables
If you use long motor cables with a high carrier frequency, the increased leakage current can cause nuisance
tripping of the thermal relay. To prevent this, decrease the carrier frequency or increase the tripping level of the
thermal overload relay.
■ Nuisance Tripping Because of High Drive Carrier Frequency
High carrier frequency PWM drives make current waveforms that can increase the temperature in overload relays.
It may be necessary to increase the trip level setting when encountering nuisance triggering of the relay.
WARNING! Fire Hazard. Before you increase the detection level of the thermal relay, make sure that a secondary problem is
not the cause of the overload. Make sure that you know the local codes for electrical wiring, then adjust the electrothermal
settings. Incorrect thermal relay adjustment and incorrect wiring can cause serious injury or death.
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