Yaskawa GA500 oL1 after running a while, output current above FLA: what to check?
My Yaskawa GA500 drive is tripping with an oL1 fault after running for a while. I've noticed the output current is consistently above the motor's full load amps (FLA). What should I check first?
The oL1 fault on a Yaskawa GA500 drive indicates a motor overload, meaning the drive's electronic thermal motor protection has tripped. This fault can only be reset once the motor overload level (U4-16) is below 100. Common causes include excessive load, incorrect motor parameters, or issues related to low-speed operation or frequent starts/stops.
Likely causes and checks
1Load too large
- Points to it
- The motor is operating under a sustained heavy load that exceeds its capacity, causing the drive's thermal protection to trip over time.
- Check
- Measure the actual output current from the drive and compare it to the motor's nameplate Full Load Amps (FLA). If the current is consistently higher, reduce the mechanical load on the motor.
2Motor rated current or base frequency set wrong
- Points to it
- If the drive's internal settings for motor rated current or base frequency do not match the actual motor nameplate values, the drive's overload calculation will be inaccurate, leading to nuisance trips.
- Check
- Verify that parameter E2-01 [Motor Rated Current (FLA)] and E1-06 [Base Frequency] are accurately set to the values specified on the motor's nameplate.
3Low-speed operation of a self-cooled motor
- Points to it
- General-purpose motors rely on their own fan for cooling, which becomes ineffective at low speeds. Prolonged operation at low speeds can lead to overheating and an oL1 trip, even under normal load.
- Check
- If the fault occurs only during extended low-speed operation, consider increasing the motor speed, reducing the load at low speeds, or using a drive-dedicated motor with L1-01 adjusted accordingly.
4Acceleration/deceleration or cycle times too short
- Points to it
- Frequent starts and stops or very short acceleration/deceleration times can cause excessive current spikes and heat buildup in the motor, leading to an overload trip.
- Check
- Review the machine's cycle times. If frequent starts and stops are occurring, increase the acceleration and deceleration times by adjusting parameters C1-01 to C1-08.
Next check: Given the symptom of tripping after running a while with output current above FLA, the most likely cause is an excessive load. Start by accurately measuring the output current and comparing it to the motor's nameplate FLA. If the current is indeed too high, investigate ways to reduce the mechanical load on the motor.
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