Motor control with contact weld sensor and interrupter
AssigneeEaton Corporation
InventorLawrence C. Corey
Life of this patent
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Abstract
A first pole of a double pole switch selectively connects a battery to a motor in one switch condition and disconnects the motor and battery in a second switch condition, wherein a second switch pole connects a dynamic braking circuit around the motor. In the event contacts of the first pole weld closed and fail to open in the second switch condition, the second pole connects the fuse directly to the battery in shunt of the motor to cause the fuse to blow and open the circuit to the motor. Alternative embodiments incorporate time delays between switch operation and blowing of the fuse by incorporating a thermistor or an R-C timing circuit.
Claims11
A motor control comprising:
- an electric power source;
- a motor;
- current responsive circuit interrupter means in circuit with said source and said motor;
- first switch means operable between closed and open conditions for selectively connecting and disconnecting, respectively, said motor to said source;
- second switch means operable substantially coincidentally with operation from said closed condition to said open condition of said first switch means for connecting a shunt path around said motor in the event said first switch means remains in said closed condition when operated toward said open condition;
- said circuit interrupter means being operable in response to increased current upon establishment of said shunt path for disconnecting said motor from said source;
Dependencies are inferred from the claim text.