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6 Cards in this Set
- Front
- Back
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Synchronous AC Motor Principles |
- Rotate same speed as magnetic field, locked at this speed. - You can control speed if you have control over frequency of supply. |
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What happens if the load is too excessive |
- Motor will stop. |
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Synchronous Motor Characteristics |
- Speed extremely stable.
- Speed controlled by frequency of applied power. |
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Synchronous Speed Formula |
- RPM = 120f/P - RPM = revolutions per minute. - f = frequency of supply. - P = number of poles per phase. |
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Cage Rotor Principles |
- Self-starting motor. - Speed always less than synchronous speed because there needs to be relative motion between conductor and relative field, enables cage to rotate. - Cage rotates in same direction of magnetic field. - Lasts long time as slip rings and brushes are not used, commutator used. |
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Process of Cage Rotor |
- Lines of magnetic field induce current in cage bar. - LH rule to discover current direction. - Use Fleming's RH grasp rule for determining magnetic field direction around bar. - Magnetic field interacts with main magnetic field, this turns the cage in direction of magentic field around cage bars. |
