How do I troubleshoot at Over Voltage (OV) trip on my Unidrive M?

This trip is generated when the DC Bus Voltage level rises above a set level. Generally, this trip occurs when a “overhauling load”, or high-inertia condition exists during deceleration. In basic terms, the motor is converting mechanical energy into electricity, or acting like a generator. This energy must have somewhere to go, which is usually back into the drives DC Bus circuit. 

There are several ways to prevent this depending on the severity of the mechanical load on the motor, (adjusting Regeneration Current limit, dynamic braking resistor or using a regenerative drive or add-on module).  General troubleshooting steps:   

• Parameter 2.004 is set to “Standard” without a DBR.  
• Parameter 2.004 is set to “Fast” if a DBR is being used. 
• Increasing the Deceleration rate in Parameter 2.021 
• Tuning the current gains in Parameters 4.013 & 4.014 to higher values (i.e. doubled from the autotune)
• Checking the DBR parameter settings  
• Determine if DBR is sized properly