Pulse excitation torque amplifier
AssigneeElectric Machinery Mfg. Company
InventorsDavid W. Schlicher, Liboslav Fabian
Life of this patent
Estimating the term…
Abstract
A starting control system for synchronous motors having circuits for detecting motor speed, the zero crossings of the current induced in the field windings, and the motor load angle. A circuit responsive to the detected motor speed, zero crossings and load angle triggers the DC excitation of the field at the zero crossings upon reaching a predetermined rotor speed and terminates the DC excitation at predetermined load angles. The pulsed DC excitation provides a torque that pulls the rotor into synchronism within several rotor slip cycles. In one embodiment the pulsed DC excitation is applied on both positive and negative half-cycles of the induced field current waveform.
Claims16
A torque amplifier control circuit for pulling a synchronous motor rotor having a field winding with the stator rotating field comprising:
- means for detecting motor speed and generating a first signal representative thereof;
- means for detecting the zero crossings of the induced field current waveform and generating a second signal representative of said zero crossings;
- means for determining the load angle of the motor and generating a third signal representative thereof;
- and
- means responsive to said first, second and third signals for applying a DC voltage to said field winding at said zero crossings when said motor speed exceeds a predetermined value, and removing said DC voltage at predetermined load angles whereby said motor is pulled into synchronism within several rotor slip cycles.
A torque amplification control circuit for pulling a synchronous motor rotor having a field winding into step with the stator rotating field comprising:
- means for detecting motor speed and generating a first signal representative thereof;
- means for detecting the zero crossings of the induced field current waveform and generating a second signal representative of said zero crossings;
- means for determining the load angle of the motor and generating a third signal representative thereof;
- means for detecting the polarity of said induced field current and generating a fourth signal representative thereof;
- means responsive to said first, second, third, and fourth signals for applying a DC voltage to said field winding at said zero crossings when said motor speed exceeds a predetermined value and removing said DC voltage at predetermined load angles, said DC voltage being of the same polarity as the induced field current.
Dependencies are inferred from the claim text.