Substituting a resistance in place of the capacitor in a capacitor-start single-phase motor results in____________?
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Answer: D. motor will continue to run in same direction
Explanation
Replacing the capacitor with a pure resistance in a capacitor start motor still provides enough phase shift. This initial phase difference between the two windings allows the rotor to start turning upon power application. Once the motor is spinning, the rotational inertia and alternating field keep it moving in the same direction. Capacitor start motors are designed to create an artificial two phase supply from a single phase source. A starting capacitor introduces a leading phase angle in the auxiliary winding current compared to the main winding. Resistance can also shift phase angles, though it introduces higher thermal losses compared to using pure capacitance.
Torque will actually decrease because resistance produces less optimal phase displacement than a reactive capacitor component. The motor will consume more power due to resistive heating losses within the newly substituted starting circuit elements. The direction of rotation depends on the initial phase lead, which remains correctly oriented to preserve forward spinning.
- Subject
- Engineering
- Category
- Electrical Engineering
- Topic
- —
- Difficulty
- medium
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