Overvoltage

What does OV mean?

This fault occurs when the DC bus voltage inside the inverter exceeds a permissible threshold. It is commonly caused by regenerative energy from the motor during rapid deceleration, an unstable input power supply, or a malfunctioning braking resistor. Sustained overvoltage can damage the inverter's DC link capacitors and power components.

• Rapid deceleration of a high-inertia load without adequate regenerative braking resistance (Parameter C2-01).
• Incoming AC line voltage exceeding the inverter's maximum permissible input voltage (e.g., >480VAC for 400V class).
• Failure of an external regenerative braking unit or its associated control circuitry.
• Faulty DC bus voltage measurement circuit within the inverter, providing an inaccurate reading.
• Harmonic distortion or instability in the input power supply causing transient voltage spikes.

Click steps to track your progress.

1. 1

   1. Measure incoming AC line voltage (L1-L2, L2-L3, L3-L1) at the inverter's input terminals using a true-RMS voltmeter.

2. 2

   2. Verify the deceleration time parameter (F2-03) is set to a value that allows the motor to slow down without excessive regeneration.

3. 3

   3. Inspect the regenerative braking resistor (if installed) for proper connection and ensure its resistance value (Ohms) matches inverter specifications.

4. 4

   4. Monitor DC bus voltage (e.g., Parameter C1-03) on the inverter's display or with an external multimeter and compare to the overvoltage trip threshold.

5. 5

   5. Check for proper operation of external line reactors or input filters, if used, which help stabilize input voltage.