## LRA - Inrush Current Definitions

## LRA - Inrush Current Definitions

(OP)

For an Induction Motor with across the line starting.

Some indicate that the initial instantaneous Inrush Current is much larger than Locked Rotor Amps (LRA ), while others state that they are the same thing.

Which is correct?

Please help this ME

Thanks in advance.

Some indicate that the initial instantaneous Inrush Current is much larger than Locked Rotor Amps (LRA ), while others state that they are the same thing.

Which is correct?

Please help this ME

Thanks in advance.

## RE: LRA - Inrush Current Definitions

## RE: LRA - Inrush Current Definitions

This is due to the presence of an exponentially decaying dc component. Model an a series R/L circuit with suddenly applied voltage of magnitude. The response has a steady state sinusoidal component and an exponentially decaying dc component. The initial value of the dc component in the worst case phase closure has the value of the peak of the sinusoidal component. This can just about double the peak. Doubling the normal peak of sqrt(2) times rms LRC gives 2*sqrt(2) times LRC max instantaneous peakl

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## RE: LRA - Inrush Current Definitions

This is a pet peave of mine. Industry professionals misue the term "inrush current" when they mean "starting current" all the time.

JRaef.com

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