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Is there a way to disable the phase imbalance during the motor start only for the C440 relays??

The phase imbalance is disabled during start-up by default for two reasons. First, the C440 requires current to being running through it for a limited time period to power up its capacitors which are used to fire the tripping mechanism. The length of this "power-up" is dependent on the running current, so we can't give a set time. Second, the phase imbalance has a built-in trip delay at all times programmed for 10 seconds. This means that the firmware in the unit will always be looking for phase imbalance, but that imbalance must be sustained at a value of 50% or greater for 10 seconds, before the device will trip. This assures no nuisance tripping. 

This means the delay for tripping on phase imbalance during start-up is at a minimum 10 seconds, and a maximum of infinity dependent on the running current charging up the capacitors. If the running current is well below the rating of the overload, the overload's capacitors don't ever charge and therefore couldn't trip on phase imbalance.

 

FAQ.

How do C440 protections work for Phase Imbalance?

How to determine over load trip setting for C440 relay from motor FLA rating ?

What causes a trip event in the C440/XTOE overload relay?