Locked Rotor Current Circuit 1

[EEBubba]

Is there any method to calculate the locked rotor current of a motor given the T-model circuit parameters?

This is an old motor and the parameters are available, but the performance data is not. I am simply trying to understand the impact of an across the line start.

Thanks,

 

[electricpete]

I assume the T model would be:

==== Z1 ====Z2(s)==
| |
Zm |

Where
Z1 = R1+jX1
Z2(s) = R2/s + jX2
Zm = jXm

If that is a T model, then computing LRC is a very simple excercize in circuit analysis.

For locked rotor conditions s=1
Ztotal(s=1)= Z1 + (Z2(1)* Zm)/(Z2(1)+Zm)

ILRC = Vterminal/Ztotal(s=1)


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[electricpete]

If your parameters are on a per-phase basis, then of course the voltage used should be line to neutral voltage.

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