Omron Q2A Series Technical Manual page 104

3.11 Dynamic Braking Option, Motor Protection
Note:
If you operate more than one motor from one drive, you cannot use the electronic thermal protection of the drive.
• 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. Make sure that a secondary problem is not the cause of the overload before you increase the
detection level of the thermal relay. Verify local ordinances for electrical wiring, then adjust electrothermal settings. Incorrect
wiring can cause death or serious injury from fire.
104 SIEPYEUOQ2A01A AC Drive Q2A Technical Manual