2.20 Dynamic Braking Option, Motor Protection
124 YASKAWA ELECTRIC SIEP C710617 05F YASKAWA AC Drive GA700 Technical Manual
The electronic thermal overload function uses the relation between the speed and heat characteristics in the
variable speed control range to simulate the cooling ability of general-purpose motors and forced-vented motors to
prevent damage to the motor.
Operating More than One Motor from One Drive
To disable the overload protection function of the electronic thermal protector of the drive, set L1-01 = 0 [Motor
Overload (oL1) Protection = Disabled].
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.
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