US 3,993,940 A · Latching system for two-phase reversible motor

Abstract

By actuating a momentary contact switch, an energizing circuit applies an AC voltage directly to one of the two field windings of a two-phase reversible AC induction motor to drive that motor in one of its two directions. As the motor begins to rotate, the shifted phase voltage appearing at the other field winding has a relatively high magnitude and this is employed to energize a neon photo coupler which then completes a holding or latching circuit for maintaining the motor energized so that it continues to rotate. If the motor stalls or if its rotation is purposely stopped, which may be caused by a limit-of-travel switch actuated by apparatus driven by the motor, the magnitude of the shifted phase voltage decreases and the neon photo coupler de-energizes, thereby disabling the holding circuit. By actuating another momentary contact switch, motor rotation in the opposite direction occurs and another holding circuit effects continued motor rotation until the motor stalls or is purposely stopped.

Claims12

Dependent claims

A latching system for maintaining a two-phase reversible AC induction motor rotating selectively in either direction, where the motor includes, in delta connection, first and second field windings and a phase shift capacitor, comprising:

an AC power source for providing an AC voltage of predetermined magnitude;
first energizing means for applying said AC voltage from said power source to the first field winding to initiate rotation of the motor in one direction;
first holding means responsive to the operation of said first energizing means and to the voltage developed across the capacitor, when the motor begins to rotate in said one direction, for maintaining the application of said AC voltage to the first field winding to effect continued motor rotation;
second energizing means for applying said AC voltage from said power source to the second field winding to initiate rotation of the motor in the opposite direction;
and second holding means responsive to the operation of said second energizing means and to the voltage developed across the capacitor, when the motor begins to rotate in said opposite direction, for maintaining the application of said AC voltage to the second field winding to effect continued motor rotation.

2 more elements

Dependencies are inferred from the claim text.

Latching system for two-phase reversible motor

Life of this patent

Latching system for two-phase reversible motor

Life of this patent

Abstract

Claims12