Abstract A starter device for a single phase A.C. motor having a main winding and a starting winding adapted for connection to a single phase A.C. source. The starter device includes a semi-conductor switching device having a control electrode and a transconductive path, and a transformer having a first and a second primary windings arranged to generate opposite fluxes in the transformer core, and a secondary winding. The starter device includes a circuit for connecting the first primary winding in series with the main winding of the motor and another circuit for connecting the second primary winding in series with the transconductive path of the switching device and with the starting winding of the motor. The control electrode of the switching device is connected to the secondary winding of the transformer whereby the voltage induced in the secondary winding by the initial inrush of current flowing through the first primary winding upon starting of the motor will render the switching device conductive to permit energization of the starting winding of the motor to start the same. The flux produced by the second primary winding shortly after initiation of conduction in the switching device will oppose the flux created by the first primary winding and so reduce the voltage induced in the secondary winding to stop conduction through the switching device and thus disconnect the starting winding of the motor.
A starter device for a single phase A.C motor having a main winding and a starting winding adapted for connection to a single phase A.C. source, comprising : a. a semi-conductor switching device having a control electrode and a transconductive path; b. a transformer having a first and a second primary windings arranged to generate opposite fluxes in the transformer core, and a secondary winding; c. circuit means for connecting said first primary winding in series with the main winding of the motor; d. circuit means for connecting said second primary winding in series with the transconductive path of the switching device and with the starting of the motor; and e. means for connecting the control electrode of said switching device to the secondary winding of said transformer, whereby the voltage induced in said secondary winding by the initial inrush of current through said first primary winding upon starting of the motor will render said switching device conductive to permit energization of the starting winding of the motor to start the motor, whereas the flux produced by said second primary winding shortly after initiation of the conduction of said switching deviCe will oppose the flux created by said primary winding and so reduce the voltage induced in the secondary winding to stop conduction through the switching device and thus disconnect the starting winding of the motor.
Claim 2
Dependent Claim
226 words
A starter device for a single phase A.C motor having a main winding and a starting winding adapted for connection to a single phase A.C. source, comprising : a. a semi-conductor switching device having a control electrode and a transconductive path; b. a transformer having a first and a second primary windings arranged to generate opposite fluxes in the transformer core, and a secondary winding; c. circuit means for connecting said first primary winding in series with the main winding of the motor; d. circuit means for connecting said second primary winding in series with the transconductive path of the switching device and with the starting of the motor; and e. means for connecting the control electrode of said switching device to the secondary winding of said transformer, whereby the voltage induced in said secondary winding by the initial inrush of current through said first primary winding upon starting of the motor will render said switching device conductive to permit energization of the starting winding of the motor to start the motor, whereas the flux produced by said second primary winding shortly after initiation of the conduction of said switching deviCe will oppose the flux created by said primary winding and so reduce the voltage induced in the secondary winding to stop conduction through the switching device and thus disconnect the starting winding of the motor.
Claim 3
Dependent Claim
50 words
A starter device as defined in claim 1, further comprising a thermistor connected across said secondary winding for absorbing the voltage surges induced in the secondary winding of the transformer due to sudden overloads on the motor during operation causing corresponding increases of the current through the first primary winding.
Claim 4
Dependent Claim
15 words
A starter device as defined in claim 1, wherein said switching device is a triac.
Claim 5
Dependent Claim
71 words
A starter device as defined in claim 1, wherein a potentiometer is connected across said secondary winding, said potentiometer having a variable tap connected to said control electrode for varying the voltage applied to said switching device and for absorbing the voltage surges induced in the secondary winding of the transformer due to sudden overloads on the motor during operation causing corresponding increases of the current through the first primary winding.