Why does an S-Flex circuit breaker trip when starting in bypass mode?

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Issue:

The S-Flex attempt to start in BYP will trip the breaker immediately.

Product Line:

S-Flex

Environment:

Models with bypass feature

Cause:

High current

Resolution:

The circuit breaker (CB) has an instantaneous trip feature. This protects circuits from short circuit or other very high currents.
In BYP mode, the motor is started with full voltage applied. The power circuit will experience a high inrush current, typically 6-10 times the motor FLA. If this initial inrush exceeds the CB instantaneous setting, it will trip immediately. The CB instant setting should be adjusted to a point above the normal inrush current for the application.
See the attached file, excerpt from the S-Flex Instruction Bulletin, 30072-451-83.

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