The current imbalance between legs of polyphase motors should never exceed what percentage?

For polyphase motors, particularly three-phase motors, maintaining a balanced current between the phases is crucial for efficient operation. An imbalance can lead to excessive heating, reduced efficiency, and may ultimately damage the motor over time.

The industry standard dictates that the current imbalance should never exceed 5%. This threshold helps ensure that the motor operates within safe limits, reducing the risk of overheating, and prolongs the lifespan of the motor. A 5% imbalance threshold allows for minor fluctuations that might occur during normal operation without significantly impacting performance or safety.

Higher percentages of imbalance, such as 10% or 15%, would typically indicate potential problems, like issues with the supply system or faults in the motor itself, which could lead to severe operational problems and necessitate immediate investigation and correction. Therefore, keeping the imbalance to 5% or less is essential for optimal motor performance and reliability.