Code oC: Overcurrent
Issue Description & Safety Warning
The Yaskawa V1000 AC Drive has triggered a critical Overcurrent alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
Code type: Fault Manual section: Yaskawa V1000 Troubleshooting The motor has been damaged due to overheating or the motor insulation is damaged. - Check the insulation resistance. - Replace the motor. One of the motor cables has shorted out or there is a grounding problem. - Check the motor cables. - Remove the short circuit and power the drive back up. - Check the resistance between the motor cables and the ground terminal. - Replace damaged cables. The load is too heavy. - Measure the current flowing into the motor. - Replace the drive with a larger capacity unit if the current value exceeds the rated current of the drive. - Determine if there is sudden fluctuation in the current level. - Reduce the load to avoid sudden changes in the current level or switch to a larger drive. The acceleration or deceleration times are too short. Calculate the torque needed during acceleration relative to the load inertia and the specified acceleration time. If the right amount of torque cannot be set, make the following changes: - Increase the acceleration time (C1-01, C1-03, C1-05, C1-07) - Increase the S-curve characteristics (C2-01 through C2-04) - Increase the capacity of the drive. The drive is attempting to operate a specialized motor or a motor larger than the maximum size allowed. - Check the motor capacity. - Ensure that the rated capacity of the drive is greater than or equal to the capacity rating found on the motor nameplate. Magnetic contactor (MC) on the output side of the drive has turned on or off. Set up the operation sequence so that the MC is not tripped while the drive is outputting current. V/f setting is not operating as expected. - Check the ratios between the voltage and frequency. - Set parameter E1-04 through E1-10 appropriately. Set E3-04 through E3-10 when using a second motor. - Lower the voltage if it is too high relative to the frequency. Excessive torque compensation. - Check the amount of torque compensation. - Reduce the torque compensation gain (C4-01) until there is no speed loss and less current.
Source: Yaskawa AC Drive V1000 Compact Vector Control Drive Technical Manual (SIEP C710606 19D)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Yaskawa V1000 AC Drive Alarms
Yaskawa controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code oC on the V1000 AC Drive identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Yaskawa's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 153 Yaskawa V1000 AC Drive codes.
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