A motor controller comprises a switch circuit and a control unit. The switch circuit is coupled to a motor for driving the motor. The control unit is configured to generate a plurality of control signals to control the switch circuit. The motor controller sequentially determines a first phase, a second phase, a third phase, and a fourth phase based on a rotation direction. When the motor controller is in the first phase and the motor controller is unable to detect a phase switching time point within a starting time, the motor controller switches from the first phase to the second phase, the third phase, or the fourth phase. The motor controller is configured to increase a success rate of starting the motor.

A motor controller comprises a switch circuit and a control unit. The switch circuit is coupled to a motor for driving the motor. The control unit is configured to generate a plurality of control signals to control the switch circuit. The motor controller sequentially determines a first phase, a second phase, a third phase, and a fourth phase based on a rotation direction. When the motor controller is in the first phase and the motor controller is unable to detect a phase switching time point within a starting time, the motor controller switches from the first phase to the second phase, the third phase, or the fourth phase. The motor controller is configured to increase a success rate of starting the motor.

System, apparatus, and methods for controlling a motor by using servo-to-edge direction feedback are disclosed. An exemplary apparatus comprises: a fiber optic rotary junction (FORJ) having a rotatable portion; a motor to rotate the rotatable portion; a connector to connect the rotatable portion to a rotatable fiber of an imaging probe; a sensor positioned in close proximity to a target and configured to output a signal indicative of which one of at least two distinguishable regions of the target is proximal to the sensor; and a controller configured to control the rotational direction of the motor based on the sensor signal. In one embodiment, the motor is a servo-motor, and the rotation of the motor and/or rotatable portion is controlled by a servo-loop to change the rotation direction of the motor back-and-forth around a predetermined rotational position without the use of an encoder.

A motor control apparatus includes control circuitry and rotation direction adjusting circuitry. The control circuitry is configured to output, in accordance with a phase sequence with respect to a motor, a drive command signal which is generated based on a motor rotation signal output from a motor rotation detector to control the motor. The rotation direction adjusting circuitry is configured to match the phase sequence with rotation direction information included in the motor rotation signal if a first trouble signal showing excessive motor current or excessive motor speed is input via an operation unit.

A motor control apparatus includes control circuitry and rotation direction adjusting circuitry. The control circuitry is configured to output, in accordance with a phase sequence with respect to a motor, a drive command signal which is generated based on a motor rotation signal output from a motor rotation detector to control the motor. The rotation direction adjusting circuitry is configured to match the phase sequence with rotation direction information included in the motor rotation signal if a first trouble signal showing excessive motor current or excessive motor speed is input via an operation unit.

A method for controlling the direction of rotation of a fluid machine having an oriented-blade impeller, comprising the following steps:

starting (100) a synchronous electric motor which operates said fluid machine until the synchronous state is reached;

driving (200) said synchronous electric motor at steady state by applying a phase cutting;

applying (300) a phase cutting corresponding to a reference power, wherein said reference power is comprised between a first power required to keep the propeller rotating in a right direction and a second power required to keep the propeller rotating in a wrong direction, which is opposed to the right direction.

A method for determining a direction of rotation for an electronically commutated motor (ECM) is described. The motor is configured to rotate a blower and the method comprises rotating the blower using the ECM and determining if the resulting blower rotation is indicative of the desired direction of rotation for the blower.

A method for determining a direction of rotation for an electronically commutated motor (ECM) is described. The motor is configured to rotate a blower and the method comprises rotating the blower using the ECM and determining if the resulting blower rotation is indicative of the desired direction of rotation for the blower.

An electric working machine in one aspect of the present disclosure includes: a motor; a driver to drive the motor; a first control circuit; and a second control circuit. The first control circuit controls the driver such that the motor rotates in a set rotation direction. The second control circuit is provided separately from the first control circuit. The second control circuit detects a rotation direction of the motor and performs an abnormality handling process to stop rotation of the motor in response to a situation where the detected rotation direction is reverse to the set rotation direction.

Examples described herein provide a method for direction control of a motor of a gate crossing mechanism. The method includes providing, by a field-effect transistor (FET) driver, a first voltage via a high output to an open contact of a first relay and to a closed contact of a second relay. The first voltage causes a shaft of the motor to turn in a first direction. The method further includes providing, by the FET driver, a second voltage via a low output to a closed contact of the first relay and to an open contact of the second relay. The second voltage causes the shaft of the motor to turn in a second direction opposite the first direction.