Safety drive circuit for pump motor
First Claim
Patent Images
1. A motor drive circuit for utilizing power from an alternating current source to drive a direct current motor which is mechanically coupled to a liquid pump, comprising:
- a) a circuit breaker connected to said alternating current source, said circuit breaker having a plurality of circuit disconnecting inputs;
b) a direct current power supply connected to said circuit breaker and to said motor;
c) a motor drive circuit connected to said motor, said motor drive circuit having at least two control inputs;
d) a pressure set circuit connected to one of said at least two control inputs, said pressure set circuit having means for presetting a desired pump output pressure;
e) a pressure sensing circuit connected to another of said at least two control inputs, said pressure sensing circuit having means for sensing said pump liquid pressure;
f) means for sensing the current passing into said power supply from said alternating current source, including means for disconnecting said circuit breaker if the sensed current exceeds a predetermined limit;
g) means for sensing the voltage of said alternating current source, including mean for activating one of said circuit breaker disconnecting inputs if the sensed voltage exceeds a predetermined limit;
h) means for sensing the current through said motor, including means for activating one of said circuit breaker disconnecting inputs if the sensed current exceeds a predetermined limit;
i) means connected to said pressure sensing circuit for sensing a predetermined maximum pressure, including means for activating one of said circuit breaker disconnecting inputs if the predetermined maximum pressure is sensed; and
j) means for sensing the difference between the preset pressure setting and the sensed output pressure and generating a difference signal, and means for comparing this difference signal with a signal representative of motor current, including means for activating one of said circuit breaker disconnecting inputs if the compared signals exceed a predetermined limit.
1 Assignment
0 Petitions
Accused Products
Abstract
A DC motor drive system for mechanically linking to a reciprocable pump, having safety circuits for disconnecting power from the system upon detection of excessive line voltage variations, excessive line current variations, excessive pressure demands, and electrical and mechanical faults which may occur in system operation.
-
Citations
9 Claims
-
1. A motor drive circuit for utilizing power from an alternating current source to drive a direct current motor which is mechanically coupled to a liquid pump, comprising:
-
a) a circuit breaker connected to said alternating current source, said circuit breaker having a plurality of circuit disconnecting inputs; b) a direct current power supply connected to said circuit breaker and to said motor; c) a motor drive circuit connected to said motor, said motor drive circuit having at least two control inputs; d) a pressure set circuit connected to one of said at least two control inputs, said pressure set circuit having means for presetting a desired pump output pressure; e) a pressure sensing circuit connected to another of said at least two control inputs, said pressure sensing circuit having means for sensing said pump liquid pressure; f) means for sensing the current passing into said power supply from said alternating current source, including means for disconnecting said circuit breaker if the sensed current exceeds a predetermined limit; g) means for sensing the voltage of said alternating current source, including mean for activating one of said circuit breaker disconnecting inputs if the sensed voltage exceeds a predetermined limit; h) means for sensing the current through said motor, including means for activating one of said circuit breaker disconnecting inputs if the sensed current exceeds a predetermined limit; i) means connected to said pressure sensing circuit for sensing a predetermined maximum pressure, including means for activating one of said circuit breaker disconnecting inputs if the predetermined maximum pressure is sensed; and j) means for sensing the difference between the preset pressure setting and the sensed output pressure and generating a difference signal, and means for comparing this difference signal with a signal representative of motor current, including means for activating one of said circuit breaker disconnecting inputs if the compared signals exceed a predetermined limit. - View Dependent Claims (2, 3, 4, 5)
-
-
6. In a motor drive circuit for utilizing power from an alternating current line, converted to a direct current voltage by a power supply to drive a direct current motor connected to a liquid pump, through a motor drive circuit, the improvement in safety circuits comprising:
-
a) a circuit breaker in said alternating current line, said circuit breaker having a plurality of sensing elements for disconnecting said line; b) means for monitoring the current through said alternating current line and for activating one of said plurality of sensing elements at a predetermined current level; c) means for monitoring the voltage of said alternating current line and for activating one of said plurality of sensing elements at a predetermined voltage level; d) means for monitoring the current through said direct current motor and for activating one of said plurality of sensing elements at a predetermined current level; e) means for monitoring the pressure of said liquid pump and for activating one of said plurality of sensing elements at a predetermined pressure level; and f) means for monitoring the motor drive circuit current and for activating one of said plurality of sensing elements at a predetermined current level. - View Dependent Claims (7, 8, 9)
-
Specification