YASKAWA P1000 Technical Manual page 391

8.5 Installing Peripheral Devices
the load current is within the motor rated value. A thermal relay cannot effectively protect the motor due to the reduction of
cooling at low speeds. For this reason, apply the UL recognized electronic thermal overload protection function built into the
drive whenever possible.
UL recognized electronic thermal overload function of the drive: Speed-dependent heat characteristics are simulated using
data from standard motors and force-ventilated motors. The motor is protected from overload using this function.
Using a Single Drive to Operate Multiple Motors
Set parameter L1-01 to 0 to disable thermal overload protection for the drive.
Note: The UL recognized electronic thermal overload function cannot be applied when operating multiple motors with a single drive.
Long Motor Cables
When a high carrier frequency and long motor cables are used, nuisance tripping of the thermal relay may occur due to increased
leakage current. To avoid this, reduce the carrier frequency or increase the tripping level of the thermal overload relay.
Nuisance Tripping Due to a High AC Drive Carrier Frequency
Current waveforms generated by high carrier frequency PWM drives tend to 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. Confirm an actual motor overload condition is not present prior to increasing the thermal oL trip setting. Check
local electrical codes before making adjustments to motor thermal overload settings. Failure to comply could result in death or serious injury.
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YASKAWA SIEP YAIP1U 01C AC Drive - P1000 Technical Manual 391