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an investigation of dual stator winding induction machines

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11.2.3 Short Circuit Test<br />

The short circuit test is used to calculate the leakage induct<strong>an</strong>ce <strong>an</strong>d the rotor<br />

resist<strong>an</strong>ce. The test is performed by blocking the rotor so it c<strong>an</strong>not rotate while a three-<br />

phase bal<strong>an</strong>ced voltage is applied to the <strong>stator</strong> <strong>winding</strong> sets. The input active power, input<br />

voltage <strong>an</strong>d phase current are measured. In this case, since the slip <strong>of</strong> the machine is<br />

equal to one, the imped<strong>an</strong>ce <strong>of</strong> the core loss resist<strong>an</strong>ce <strong>an</strong>d the mutual induct<strong>an</strong>ce are so<br />

big compared with the imped<strong>an</strong>ce <strong>of</strong> the rotor leakage induct<strong>an</strong>ce <strong>an</strong>d rotor resist<strong>an</strong>ce<br />

that the current flowing through the imped<strong>an</strong>ce <strong>of</strong> the core loss resist<strong>an</strong>ce <strong>an</strong>d the mutual<br />

induct<strong>an</strong>ce c<strong>an</strong> be ignored. The equivalent circuit <strong>of</strong> the short circuit test is shown in<br />

Figure 11.3.<br />

V ph<br />

rs<br />

Lls<br />

I ph<br />

Figure 11.3 Per phase equivalent circuit <strong>of</strong> <strong>an</strong> <strong>induction</strong> machine for the short circuit test<br />

Therefore the machine parameters c<strong>an</strong> be calculated by:<br />

V<br />

I<br />

sc<br />

sc<br />

=<br />

=<br />

' ( rs<br />

+ r<br />

) + j(<br />

X ls + X lr )<br />

' ( rs<br />

+ r<br />

) + j2<br />

X ls<br />

( ) 2<br />

r r I<br />

425<br />

'<br />

Llr<br />

'<br />

rr<br />

(11.7)<br />

P sc = 3 s + r sc<br />

(11.8)

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