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# Phase Sensitive Divider Control

IP.com Disclosure Number: IPCOM000096916D
Original Publication Date: 1962-Jan-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 35K

IBM

## Related People

VanWinkle, HE: AUTHOR

## Abstract

In the movement of an elevator, more force is required to move it up against gravity than down with gravity aiding. The circuit recognizes this difference in force required to move elevator 10. Servo motor 12, which drives elevator 10 through gearing 14, has an A. C. tachometer 16 fixed to its shaft. Servo motor control 18 receives either an up signal or a down signal to cause the rotation of 12 in one or the other direction. When motor 12 turns to move elevator 10 up, the output of tachometer 16 at windings 20 is in phase with the output from a 60 cycle excitation at 22, used as a reference signal. Both windings 20 and 22 connect to phase sensitive divider bridge 24. When motor 12 rotates to move elevator 10 down, the output of 16 at winding 20 is 180 degrees out of phase with the reference at winding 22.

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Phase Sensitive Divider Control

In the movement of an elevator, more force is required to move it up against gravity than down with gravity aiding. The circuit recognizes this difference in force required to move elevator 10. Servo motor 12, which drives elevator 10 through gearing 14, has an A. C. tachometer 16 fixed to its shaft. Servo motor control 18 receives either an up signal or a down signal to cause the rotation of 12 in one or the other direction. When motor 12 turns to move elevator 10 up, the output of tachometer 16 at windings 20 is in phase with the output from a 60 cycle excitation at 22, used as a reference signal. Both windings 20 and 22 connect to phase sensitive divider bridge 24. When motor 12 rotates to move elevator 10 down, the output of 16 at winding 20 is 180 degrees out of phase with the reference at winding 22.

Bridge 24 provides an output signal which is equal to its input signal, when the output at 20 is in phase with the signal at 22. When they are 180 degrees out of phase, there is a lesser output signal. This lesser signal is applied through servo amplifier 26 to control 18 to apply a reduced torque to elevator 10 when it is moving down. This provides the necessary differential in torque for efficient operation of the elevator in either direction.

In the bridge 24, the reference signal from 22 is applied through transformer
28. This reference signal is always of greater amplitude than tachometer output
20. When the tachometer signa...