Rotation control circuit for transistor motor

Claim 2

A rotation control circuit for a transistor motor including a rotor, a stator having a plurality of stator windings, transistors defining a driving circuit connected in series with the stator windings respectively, and means for switching the transistors on and off in time sequence: said rotation control circuit comprising; means for forming a control signal responsive to the rotation speed of the rotor; and a control switching circuit means which comprises a transistor having the control signal applied to its base and performing a switching action, a resistor and a capacitor connected between the base and the emitter of the transistor, said collector of said transistor being connected to the emitter of the transistor of the driving circuit, said control switching circuit means controlling the base bias of the transistor of the driving circuit, applying a maximum voltage to the driving circuit at the starting time of rotation of the rotor, and performing a switching action and controlling the voltage applied on the driving circuit at the time of normal rotation of the rotor.

Claim 3

The rotation control circuit of claim 1, which further comprises resistors respectively connected to the bases of the transistors of the driving circuit; a variable resistor connected in series to the each of the resistors; and a power source having a plus side and a minus side; said variable resistor and the emitter of the transistor of said control switching circuit being connected to the plus side of the power source, and said stator windings being connected between the collectors of the transistors of the driving circuit and the minus side of the power source.

Claim 4

A rotation control circuit for a transistor motor including a rotor, a stator having a plurality of stator windings, transistors connected in series with the stator windings respectively, and means for switching the transistors on and off in time sequence; said rotation control circuit comprising; a switching transistor connected in series with all of the transistors of the motor, said switching transistor being normally in its conductive state; means for applying a direct current voltage across said switching transistor and the plurality of stator windings; a parallel combination circuit of a capacitor and a resistor connected between the collector and emitter electrodes of said switching transistor; and bias means responsive to rotation speeds of the rotor which exceed a predetermined speed for applying to said switching transistor a bias voltage which renders said switching transistor non-conductive whereby a reduced direct current flows to the stator windings through the transistors of the motor and said parallel combination circuit from the direct current applying means.

Claim 5

A rotation control circuit for a transistor motor including a rotor, a stator having a plurality of stator windings, transistors connected in series with the stator windings respectively, and means for switching the transistors on and off in time sequence; said rotation control circuit comprising; a switching transistor connected in series with all of the transistors of the motor, said switching transistor being normally in its conductive state; means for applying a direct current voltage across said switching transistor and the plurality of stator windings; a parallel combination circuit of a capacitor and a resistor connected between the collector and emitter electrodes of said switching transistor; and bias means responsive to rotation speeds of the rotor which exceed a predetermined speed for applying to said switching transistor a bias voltage which renders said switching transistor non-conductive whereby a reduced direct current flows to the stator windings through the transistors of the motor and said parallel combination circuit from the direct current applying means.

Claim 6

The rotation control circuit of claim 3, wherein said bias means comprises a first circuit including a first transistor which is normally in a cut off state, said first circuit rendering the first transistor into a conductive state in response to a level of a counter electromotive voltage which is generated in the stator windings in proportion to the rotation speed of the rotor, said level corresponding to the predetermined speed of the rotor, a second circuit coupled to the first circuit in cascade connection, said second circuit including a second transistor which is normally in a conductive state, said second circuit rendering the second transistor into a cut off state to the conductive state, a second parallel combination circuit of a capacitor and a resistor connected between the emitter and base electrodes of the switching transistor, and means for applying the direct current voltage across the emitter electrode of the switching transistor and the emitter electrode of the seCond transistor.

Claim 7

The rotation control circuit of claim 4 which further comprises resistors respectively connected to the bases of the transistors of the motor; a variable resistor connected in series with all of said resistors; and means for applying the direct current voltage across said variable resistor and the plurality of stator windings.