The speed of a squirrel-cage induction motor can be controlled by all of the following except_____________?
Correct answer: C. changing winding resistance
- A. changing supply frequency
- B. changing number of poles
- C. changing winding resistance
- D. reducing supply voltage
Explanation
A squirrel-cage rotor has permanently short-circuited bars, so its rotor resistance cannot be changed externally as in a wound-rotor motor. Frequency, pole number, and to a limited extent voltage can influence its speed.
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