초록 ▼

A method and system for providing assured start-up of a multi-pole permanent magnet electric motor from an at rest position. A vane is mounted on the rotational axis of the motor for rotation therewith. The vane includes a plurality of radially projecting portions each of which is maintained in a fi

A method and system for providing assured start-up of a multi-pole permanent magnet electric motor from an at rest position. A vane is mounted on the rotational axis of the motor for rotation therewith. The vane includes a plurality of radially projecting portions each of which is maintained in a fixed angular relationship with a different one of the poles of the motor. A first and second pair of sensors are mounted in a fixed angular relationship with the stator of the motor, the second pair of sensors being spaced further apart than the first pair. The sensors generate a signal when one of the protecting portions of the vane passes through them. A control circuit receives input selectively from either the first sensor pair, under normal motor operation, or from the second pair of sensors when the motor is starting. The control circuit controls the direction of current flow through the motor in response to signals from the selected pair of sensors. When the motor is starting from an at rest position, The control circuit energizes the motor to turn in a predetermined direction. If the motor turns in the opposite direction, the current through the motor is reversed after the motor has turned a predetermined angular distance. Normal operation then begins.

대표청구항 ▼

A system for providing assured start up of a multi-pole permanent magnet electric motor from an at rest position, said motor having at least one zero torque detent, comprising: a flag means mounted on the rotational axis of the motor for rotation with the motor; an electrical power source; a control

A system for providing assured start up of a multi-pole permanent magnet electric motor from an at rest position, said motor having at least one zero torque detent, comprising: a flag means mounted on the rotational axis of the motor for rotation with the motor; an electrical power source; a control circuit for controlling delivery of power from the power source to the stator of the motor, the control circuit including a first and second pair of sensors mounted in a fixed angular relationship with the stator of the motor, each sensor having a sensing region through which the flag means passes as the motor turns, each sensor generating a signal indicative of the presence or absence of the flag means in the sensing region, the first pair of sensors being mounted at a first predetermined angular distance from the zero torque detent, and the second pair of sensors being mounted at a second predetermined angular distance from the zero torque detent, said second predetermined angular distance being greater than the first predetermined angular distance; the control circuit including means for responding to the signals generated by the sensors to control the direction of current flow through the stator of the motor; said control circuit operative to energize the motor to turn in a first direction when the motor is starting from an at rest position and including means for determining the direction of movement and angular position of the rotor as a function of the signals generated by at least the second pair of sensors as the motor starts from an at rest position, and further operative to energize the motor to turn in the opposite direction if the motor has turned in a direction opposite to said first direction far enough past one of the second pair of sensors, so that the motor, upon reversing direction and reaching the torque detent, has enough rotational kinetic energy to overcome the motor\s inherent reluctance torque and begin normal operation.