The voltage unbalance between phases will impact the operation of an electric motor. An electric motor may be de-rated when operating on unbalances under 5%. The effects of voltage unbalance are:
- Reduced locked rotor and breakdown torques for the application.
- Slight reduction of full load speed
- Current will also show significant unbalance that is related to the specific motor design.
- Significant operating temperatures may result. For instance, a 3.5% voltage unbalance will result in a 25% increase in temperature rise.