Abstract: A speed control and stall protection system 10 for an electric DC brush motor includes a DC brush motor M. At least one relay K3 is connected between the motor and a power supply. A speed sensing circuit 20 is constructed and arranged to generate a signal indicative of a speed of the motor. A motor control and protection circuit 116 is constructed and arranged to receive 1) the signal from the speed sensing circuit and 2) a control signal input for operating the at least one relay to control operation of the motor. When a stall condition is determined based on the signal from the speed sensing circuit, the motor control and protection circuit is constructed and arranged to control the at least one relay to disconnect power to the motor.

Abstract: A stator and armature assembly 12 is provided for a permanent magnet DC motor. The assembly includes an armature 13 having a lamination core 14 and windings 15, and a stator structure 16 associated with the armature. The armature is constructed and arranged to rotate with respect to the stator structure. The stator structure includes at least one permanent magnet 22 providing a certain flux, and at least one wound core structure 17 having a core 18 and a coil 19 wound about the core so as to define an alternate pole with respect to the permanent magnet. When current to the coil is controlled, flux of the stator structure 16 can be increased or decreased relative to the certain flux. In this way a motor can operate at different speeds.

Abstract: A stator and armature assembly 12 is provided for a permanent magnet DC motor. The assembly includes an armature 13 having a lamination core 14 and windings 15, and a stator structure 16 associated with the armature. The armature is constructed and arranged to rotate with respect to the stator structure. The stator structure includes at least one permanent magnet 22 providing a certain flux, and at least one wound core structure 17 having a core 18 and a coil 19 wound about the core so as to define an alternate pole with respect to the permanent magnet. When current to the coil is controlled, flux of the stator structure 16 can be increased or decreased relative to the certain flux. In this way a motor can operate at different speeds.

Abstract: A stator and armature assembly 12 is provided for a permanent magnet DC motor. The assembly includes an armature 13 having a lamination core 14 and windings 15, and a stator structure 16 associated with the armature. The armature is constructed and arranged to rotate with respect to the stator structure. The stator structure includes at least one permanent magnet 22 providing a certain flux, and at least one wound core structure 17 having a core 18 and a coil 19 wound about the core so as to define an alternate pole with respect to the permanent magnet. When current to the coil is controlled, flux of the stator structure 16 can be increased or decreased relative to the certain flux. In this way a motor can operate at different speeds.

Abstract: A stator and armature assembly 12 is provided for a permanent magnet DC motor. The assembly includes an armature 13 having a lamination core 14 and windings 15, and a stator structure 16 associated with the armature. The armature is constructed and arranged to rotate with respect to the stator structure. The stator structure includes at least one permanent magnet 22 providing a certain flux, and at least one wound core structure 17 having a core 18 and a coil 19 wound about the core so as to define an alternate pole with respect to the permanent magnet. When current to the coil is controlled, flux of the stator structure 16 can be increased or decreased relative to the certain flux. In this way a motor can operate at different speeds.

Abstract: A method of detecting a rotor condition of a dc motor is provided. The motor 14 is part of a motor control circuit 10 having a free-wheeling diode 20 in parallel with the motor 14. The method establishes a threshold voltage for back emf voltage evaluation. The motor is energized to operate at a certain speed. Current is cut-off to the motor via a switch 16 for a time sufficient for current through the free-wheeling diode to decay to zero. The back emf voltage detected at leads of the motor is then compared via a comparator 21 to the threshold voltage.

Abstract: A speed control and stall protection system 10 for an electric DC brush motor includes a DC brush motor M. At least one relay K3 is connected between the motor and a power supply. A speed sensing circuit 20 is constructed and arranged to generate a signal indicative of a speed of the motor. A motor control and protection circuit 116 is constructed and arranged to receive 1) the signal from the speed sensing circuit and 2) a control signal input for operating the at least one relay to control operation of the motor. When a stall condition is determined based on the signal from the speed sensing circuit, the motor control and protection circuit is constructed and arranged to control the at least one relay to disconnect power to the motor.

Abstract: A system and method for protecting a motor from a stall condition includes a brush motor 11 having power brushes 14 and 16 that convey power to windings of the motor, and one sensing brush 20 constructed and arranged to sense a speed of rotation of an armature motor. A controller 23 is constructed and arranged to compare a sensed speed of rotation with a minimum speed value that is indicative of a stall condition. A relay 28 is constructed and arranged to disconnect power to the motor if the sensed speed is below the minimum speed value.

Abstract: A jump bar shunt structure 30 includes a base 32 constructed and arranged to be mounted to a substrate and to function as a current shunt; a pair of first legs 34 and 36 integral with the base and being constructed and arranged to be connected between terminals of at least two power devices such as MOSFETs; and a pair of second legs 50 and 52 integral with the base and being constructed and arranged to be connected to a printed circuit board so as to define a current sensing connection. The jump bar shunt structure is a single component that carries high current between two or more power devices and converts current into voltage that is used by the current measurement circuitry. The advantage of the jump bar shunt structure is that no high current (motor current) flows through a control PCB.

Abstract: A jump bar shunt structure 30 includes a base 32 constructed and arranged to be mounted to a substrate and to function as a current shunt; a pair of first legs 34 and 36 integral with the base and being constructed and arranged to be connected between terminals of at least two power devices such as MOSFETs; and a pair of second legs 50 and 52 integral with the base and being constructed and arranged to be connected to a printed circuit board so as to define a current sensing connection. The jump bar shunt structure is a single component that carries high current between two or more power devices and converts current into voltage that is used by the current measurement circuitry. The advantage of the jump bar shunt structure is that no high current (motor current) flows through a control PCB.

Abstract: A method of detecting a rotor condition of a dc motor is provided. The motor 14 is part of a motor control circuit 10 having a free-wheeling diode 20 in parallel with the motor 14. The method establishes a threshold voltage for back emf voltage evaluation. The motor is energized to operate at a certain speed. Current is cut-off to the motor via a switch 16 for a time sufficient for current through the free-wheeling diode to decay to zero. The back emf voltage detected at leads of the motor is then compared via a comparator 21 to the threshold voltage.