Browse Prior Art Database

Phase Slipping of Synchronous Motors

IP.com Disclosure Number: IPCOM000095905D
Original Publication Date: 1964-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Callahan, EJ: AUTHOR [+2]

Abstract

Circuit 10 obtains slipping or cogging of synchronous motor 12, of the variable reluctance or of the permanent magnet type, one pole position at a time to phase properly driven cylinder 14.

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Phase Slipping of Synchronous Motors

Circuit 10 obtains slipping or cogging of synchronous motor 12, of the variable reluctance or of the permanent magnet type, one pole position at a time to phase properly driven cylinder 14.

To initiate the operation of circuit 10, motor start button 15 is pressed temporarily to turn on transistor 32 and close relay contact 35 which, in turn, closes relay contact 30. As a result, AC power 22 is connected to motor 12 which comes up to synchronous speed. If 0 Degrees sync pulse C applied to line 16 occurs during the time that the gate pulse from pickup coil 24 generated by magnet 25 on driven cylinder 14 appears on line 26 or logic unit 18, motor 12 is in the proper phase. Logic unit 18 then applies a -V voltage to terminal 40 to keep transistor 32 conducting and thus maintaining power applied to motor 12.

If motor 12 is not phased properly, i.e., 0 Degrees sync pulse C does not occur during the gate pulse time, transistor 32 turns off and AC power 22 is removed from motor 12 which starts slowing down. Magnet pulses S1...S4 are generated in pickcoil 34 by magnets M1...M4 on motor 12. The pulses are applied to junction 28 between diodes 33 and 36. These then start lagging full- wave rectified power line voltage pulses W1...W4 generated by rectifier 44. These pulses are also applied to terminal 28 by an increasing phase angle until a negative portion of a magnet pulse occurs in the vicinity of the next power line voltage null. The negative pulse portion gates transistor 32 back on through diode 36 to restore power to mo...