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Constant Speed Induction Motor

IP.com Disclosure Number: IPCOM000092849D
Original Publication Date: 1967-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Johnson, CF: AUTHOR [+2]

Abstract

This single-phase induction motor maintains a constant speed under varying load conditions. Constant speed is maintained by instantaneously changing the phase relationship between the primary winding and the starting winding of the motor as load conditions vary. Motor 1, having main winding 3 and start winding 5, has load 7 connected to its armature. Single-phase AC current is applied to winding 3 and is applied to start winding 5 through capacitor 9 and silicon control rectifier 11. Capacitor 9 functions to shift the phase of the current in winding 5 from the current in winding 3 in order to develop a torque. Rectifier 11 is gated on and off in accordance with the voltage variation on its control element 13.

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Constant Speed Induction Motor

This single-phase induction motor maintains a constant speed under varying load conditions. Constant speed is maintained by instantaneously changing the phase relationship between the primary winding and the starting winding of the motor as load conditions vary. Motor 1, having main winding 3 and start winding 5, has load 7 connected to its armature. Single-phase AC current is applied to winding 3 and is applied to start winding 5 through capacitor 9 and silicon control rectifier 11. Capacitor 9 functions to shift the phase of the current in winding 5 from the current in winding 3 in order to develop a torque. Rectifier 11 is gated on and off in accordance with the voltage variation on its control element 13.

Attached to the armature of motor 1 is rotating light transmission device 15. This has a pattern which causes the resistance of light dependent resistor 17 to vary. Such is in accordance with the amount of light transmitted from light source 19 through device 15. The speed of device 15 and its pattern are such that rectifier 11 gates current through winding 5 which varies at the same frequency as the current in winding 3. The speed at which the two currents have the same frequency or have components at the same frequency is the operating speed of motor 1.

If load 7 changes thus changing the torque requirements of motor 1, the phase of the winding 5 current automatically shifts an amount sufficient to adjust the torque while hol...