SOLID STATE POWER CONTROLLER FOR DC PERMANENT MAGNET AND SHUNT FIELD WINDING MOTORS SUPPLIED FROM AN AC SOURCE
First Claim
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1. In a controller for connecting the armature of a DC permanent magnet or shunt-type motor to a source of alternating voltage supply and varying the current supplied thereto, in combination:
- an actuating lever, switch means responsive to a given amount of initial movement of said actuating lever to connect the controller to a source of alternating voltage supply, current control means including a controllable bidirectional semiconductor device and a control network responsive to additional movement of said actuating lever to control the flow of current through said semiconductor device during opposite half-cycles of connected alternating voltage supply in accordance with the amount of additional movement of said actuating lever, a full wave rectifier bridge connected in circuit with said semiconductor device and with the armature of a permanent magnet motor to insure current flow through such armature always in the same direction during opposite half-cycles of the alternating voltage supply, and a resistor connected across the AC input terminals of said rectifier bridge.
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Abstract
A solid state switching circuit and power controller for permanent magnet and shunt field winding motors used in portable power tools and the like. The power controller employs a bidirectional thyristor triode and trigger diode for varying the current supplied to the motor armature, and a full-wave rectifier bridge to establish unidirectional current flow through the motor armature on opposite half cycles of the AC power supply. A resistor across the AC terminals of the rectifier bridge enhances control action under light loads.
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1 Claim
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1. In a controller for connecting the armature of a DC permanent magnet or shunt-type motor to a source of alternating voltage supply and varying the current supplied thereto, in combination:
- an actuating lever, switch means responsive to a given amount of initial movement of said actuating lever to connect the controller to a source of alternating voltage supply, current control means including a controllable bidirectional semiconductor device and a control network responsive to additional movement of said actuating lever to control the flow of current through said semiconductor device during opposite half-cycles of connected alternating voltage supply in accordance with the amount of additional movement of said actuating lever, a full wave rectifier bridge connected in circuit with said semiconductor device and with the armature of a permanent magnet motor to insure current flow through such armature always in the same direction during opposite half-cycles of the alternating voltage supply, and a resistor connected across the AC input terminals of said rectifier bridge.
Specification