27.02.2013 Views

an investigation of dual stator winding induction machines

an investigation of dual stator winding induction machines

an investigation of dual stator winding induction machines

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

The assumption in the calculations are the core loss resist<strong>an</strong>ce is so big compared<br />

with the imped<strong>an</strong>ce <strong>of</strong> the mutual induct<strong>an</strong>ce that the voltage drops on the <strong>stator</strong><br />

resist<strong>an</strong>ce c<strong>an</strong> be neglect at this time. Then, the open circuit equivalent resist<strong>an</strong>ce is equal<br />

to the <strong>stator</strong> resist<strong>an</strong>ce <strong>an</strong>d the react<strong>an</strong>ce is equal to the sum <strong>of</strong> the <strong>stator</strong> leakage<br />

react<strong>an</strong>ce <strong>an</strong>d magnetizing react<strong>an</strong>ce. As the <strong>stator</strong> leakage react<strong>an</strong>ce <strong>an</strong>d resist<strong>an</strong>ce have<br />

been calculated from the other two tests performed, the magnetizing react<strong>an</strong>ce is<br />

calculated.<br />

r = R<br />

(11.3)<br />

s<br />

o<br />

X m X o − X1s<br />

L<br />

m<br />

= (11.4)<br />

X m<br />

= (11.5)<br />

2πf<br />

f = supply frequency = 60 Hz<br />

P<br />

input<br />

2<br />

2 Vo<br />

X m<br />

= 3rs<br />

Io<br />

+ 3<br />

(11.6)<br />

R 2πf<br />

c<br />

Both the magnetizing induct<strong>an</strong>ce <strong>an</strong>d the core loss resist<strong>an</strong>ce c<strong>an</strong> be calculated by the<br />

open circuit test. The input terminal voltage for the open circuit test ramps down from 1.2<br />

times <strong>of</strong> rated voltage <strong>an</strong>d stop when the phase current increases instead <strong>of</strong> decreasing.<br />

The Experimental results <strong>of</strong> magnetizing flux vs magnetizing induct<strong>an</strong>ce Lm1 (2-pole<br />

<strong>winding</strong> set) <strong>an</strong>d three times magnetizing induct<strong>an</strong>ce Lm2 (6-pole <strong>winding</strong> set) are shown<br />

in Figure 8.2.<br />

424

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!