Speed control system for dc motors

Claim 2

A speed control system for a DC motor, comprising a resistor bridge circuit having an armature as one of the arms thereof and being balanced with said armature locked, voltage supply means connected to said bridge for supplying a voltage to the feed terminals thereof, transistor circuit means including at least one transistor connected across the detection terminals for comparing the differential voltage between the detection terminals of said bridge circuit with a reference voltage, a first resistor connected in series with the base of said transistor to one detection terminal, and a second resistor connected between the base and the emitter of said transistor so that the current through said first resistor passes mainly through said second resistor, and means for controlling said voltage supply means so as to regulate the feed terminal voltage of said bridge circuit in accordance with the output of said transistor.

Claim 3

A speed control system as defined in claim 1, wherein at least one of said resistor connected in series with the base of said transistor and said resistor connected between the base and the emitter of said transistor is of a variable type.

Claim 4

In a speed control system for a DC motor including a bridge circuit having an armature as one of the arms thereof and being balanced with said armature locked, a voltage source providing a feed terminal voltage to said bridge circuit, and control means for controlling the feed terminal voltage supplied to said bridge circuit regulation means for regulating said control means in accordance with the detection terminal voltage of said bridge circuit, comprising a transistor, first circuit means for connecting the base of said transistor with the detection terminal of the branch of said bridge circuit not including said armature, second circuit means for connecting the emitter of said transistor with the detection terminal of the branch of said bridge circuit including said armature, at least one of said first and second circuit means including a constant-voltage circuit for biasing the detection terminal voltage by a predetermined constant voltage in the forward direction with respect to the base-emitter channel of said transistor, a first resistor connected in series with the base of said transistor, and a second resistor connected between the base and the emitter of said transistor so that the current through said first resistor passes mainly through said second resistor.

Claim 5

In a speed control system for a DC motor including a bridge circuit having an armature as one of the arms thereof and being balanced with said armature locked, a voltage source providing a feed terminal voltage to said bridge circuit, and control means for controlling the feed terminal voltage supplied to said bridge circuit regulation means for regulating said control means in accordance with the detection terminal voltage of said bridge circuit, comprising a transistor, first circuit means for connecting the base of said transistor with the detection terminal of the branch of said bridge circuit not including said armature, second circuit means for connecting the emitter of said transistor with the detection terminal of the branch of said bridge circuit including said armature, at least one of said first and second circuit means including a constant-voltage circuit for biasing the detection terminal voltage by a predetermined constant voltage in the forward direction with respect to the base-emitter channel of said transistor, a first resistor connected in series with the base of said transistor, and a second resistor connected between the base and the emitter of said transistor so that the current through said first resistor passes mainly through said second resistor.

Claim 6

A speed control system for a DC motor comprising a resistor bridge circuit having an armature as one of the arms and arranged so as to be balanced with said armature being locked, a detection transistor, means providing a constant voltage drop connected between the detection terminal of a branch including said armature of said resistor bridge circuit and the emitter of said detection transistor, a first resistor connected between the branch of said bridge circuit not including said armature and the base of said detection transistor, a second resistor connected between the base and the emitter of said transistor so that the current through said fiRst resistor passes mainly through said second resistor, and means for controlling the feed terminal voltage of said resistor bridge circuit in accordance with the collector current of said detection transistor.

Claim 7

A speed control system for a DC motor comprising a resistor bridge circuit having an armature as one of the arms and arranged so as to be balanced with said armature being locked, a detection transistor, means providing a constant voltage drop connected between the detection terminal of a branch including said armature of said resistor bridge circuit and the emitter of said detection transistor, a first resistor connected between the branch of said bridge circuit not including said armature and the base of said detection transistor, a second resistor connected between the base and the emitter of said transistor so that the current through said fiRst resistor passes mainly through said second resistor, and means for controlling the feed terminal voltage of said resistor bridge circuit in accordance with the collector current of said detection transistor.

Claim 8

A speed control system for a DC motor comprising a resistor bridge circuit having an armature as one of the arms thereof and being balanced with said armature locked, a detection transistor, a first circuit for connecting the emitter of said detection transistor with the detection terminal of the branch of said bridge circuit including said armature, constant-voltage means for biasing the detection terminal voltage of the branch of said bridge circuit not including said armature in the forward direction with respect to the base-emitter channel of said detection transistor, said constant-voltage means being connected to the detection terminal of said branch not including said armature, a first resistor for connecting the base of said detection transistor with said constant-voltage means, a second resistor connected between the base and the emitter of said detection transistor so that the current through said first resistor passes mainly through said second resistor, and means for controlling the feed terminal voltage of said bridge circuit in accordance with the collector current of said detection transistor.

Claim 9

A speed control system for a DC motor comprising a resistor bridge circuit having an armature as one of the arms thereof and being balanced with said armature locked, a detection transistor, a first circuit for connecting the emitter of said detection transistor with the detection terminal of the branch of said bridge circuit including said armature, constant-voltage means for biasing the detection terminal voltage of the branch of said bridge circuit not including said armature in the forward direction with respect to the base-emitter channel of said detection transistor, said constant-voltage means being connected to the detection terminal of said branch not including said armature, a first resistor for connecting the base of said detection transistor with said constant-voltage means, a second resistor connected between the base and the emitter of said detection transistor so that the current through said first resistor passes mainly through said second resistor, and means for controlling the feed terminal voltage of said bridge circuit in accordance with the collector current of said detection transistor.