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18 Cards in this Set
- Front
- Back
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Split Phase motors operate on the principle of |
The rotating magnetic field |
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With single phase sources the creation of a rotating magnetic field require current to be split between |
2 different windings (starting & running) in order to create a two phase system |
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For 2 phase the waves have to be __ degrees out of phase. |
90 |
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Starting Winding characteristics |
-smaller gauge wire -wound closer to pole face -high resistance/low reactance |
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Running Winding characteristics |
-Larger gauge wire -Wound closer to bottom of stator core -Low resistance/high reactance |
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The higher resistance of the start winding limits the |
Degree to witch the current in the start winding legs the applied voltage |
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The result of a phase shift is the |
Creation of a rotating magnetic field in the stator of the motor |
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Speed at witch the magnetic field of the stator rotates is based on |
-Number if poles per phase -frequency of applied voltage |
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The amount of starting torque developed by a split phase motor is determined by |
-Strength of the magnetic field of the stator -Strength of the magnetic field of the rotor -Phase angle difference between current in the start and run windings. |
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You must disconnect the start winding when the motor reaches ___% of its rated speed. This is done to protect the _____ from excessive current flow. |
75%, start winding |
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A mechanical device mounted to the shaft of the motor. When motor reaches 75% speed g force opens up the start contacts. |
Centrifugal Switch |
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Serves to both disconnect the start winding as well as provide overload protection to the motor. |
Hot-wire relay |
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A hot-wire relay is a _____ device that when subjected to heat exspands/contracts to open the connected circuit. |
Bi-metalic |
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Utilizes small solenoid operated device to disconnect start winding |
Current Relay |
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Highly reliable, and relatively inexpensive, the _____ utilizes a thermistor connect in series with the start winding. |
Solid-state starting relay |
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- Utilizes high resistance start winding/high reactance run windings |
Resistance Start- Induction Run |
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Resistance Start- Induction Run is ideal for |
-Limited duty cycle applications -Low HP/ Low Torque operations -Typical HP range 1/20HP - 1/3 HP |
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Capacitor Start -Capacitor Run has a different |
Winding construction (Start winding I'd used continously) |
