In order to improve a trailer coupling, comprising a ball neck, which is movable between a working position and a rest position and has a pivot bearing body arranged at a first end and a coupling ball arranged at a second end, a pivot unit, which is arranged fixed to a vehicle and by means of which the pivot bearing body is pivotal for the purpose of performing a pivotal movement about a pivot axis between a working position and a rest position, wherein the pivot unit comprises a pivot bearing unit fixed to the vehicle and a rotation-blocking device for blocking a pivotal movement of the pivot bearing body about the pivot axis, at least in the working position, the improvement being such that this susceptibility to faults in a trailer coupling of the kind mentioned in the introduction is avoided, it is proposed that a pivot control unit should be integrated within the pivot unit.

A motor drive control device capable of determining a drive state of a motor is provided. The motor drive control device includes a plurality of motor drive circuits performing, based on drive control signals (Sca1 and Sca2) for controlling the number of rotations of a motor, control of energization of the motor and outputting FG signals (fg1 and fg2) having a cycle corresponding to the actual number of rotations of the motor, a composite signal generation circuit receiving an input of each of the FG signals output from the motor drive circuits and generating a composite signal by combining input signals, and a drive control circuit generating, based on a speed command signal indicating a target number of rotations of the motor, the drive control signals and outputting the drive control signals to each of the motor drive circuits. The FG signals output from the motor drive circuits have a phase difference from each other.

An apparatus includes a controller. To control current through a motor winding, the controller monitors a magnitude of current supplied through the motor winding. The controller compares the magnitude of current to a threshold value. In response to detecting that the magnitude of current crosses the threshold value, the controller terminates a flow of the current through the motor winding. In one application, termination of the current through the motor winding supports more efficient use of energy to drive the motor winding. For example, via the controller, terminating the current through the motor winding to prevent the current from flowing in a reverse direction through the motor winding.

The application provides a method and device for adjusting a permanent magnet motor, an equipment, and a storage medium. The method includes the following operations. An electronic equipment acquires a counter electromotive force (CEMF) parameter, information of an electromagnetic structure of a permanent magnet motor to be adjusted and a minimum impedance value of any short-circuited coil of the permanent magnet motor to be adjusted, to determine an operational time of the short-circuited coil. The electronic equipment further judges, according to the operational time of the short-circuited coil, whether an adjustment instruction is required to be transmitted to a production equipment. When the operational time is inconsistent with a preset time, the electronic equipment transmits the adjustment instruction to the production equipment. The production equipment adjusts, according to the adjustment instruction, the electromagnetic structure of the permanent magnet motor to be adjusted. Through the method of the application, a rail transit vehicle may keep running for the preset time safely after an inter-turn short circuit failure occurs to the permanent magnet motor, and the operational safety of the rail transit vehicle is improved.

Provided is an electric seat control apparatus for a vehicle including: a first rail and a second rail mounted at a constant interval on the floor surface of a vehicle body in the forward and rearward directions of a seat; a first movement unit provided with a first motor and mounted between the first rail and the lower surface of the seat to move linearly along the first rail; a second movement unit provided with a second motor and mounted between the second rail and the lower surface of the seat to move linearly along the second rail; and a control unit that simultaneously receives the RPM and a rotational position signal of the first motor and the RPM and a rotational position signal of the second motor to synchronize the RPMs and rotational positions of the first motor and the second motor to match each other.

Selectable current limiting for a power tool. One embodiment provides a method for selectable current limiting for a power tool including determining, using a current sensor, an average current and determining whether the average current exceeds a predetermined current threshold. The method also includes determining a deviation of the average current from the predetermined current threshold and reducing a PWM duty ratio proportional to the deviation of the average current from the predetermined current threshold. The PWM duty ratio corresponds to a PWM signal provided to an inverter bridge.

A current detection unit includes current detection elements provided to phases on a high potential side of an upper arm element or on a low potential side of a lower arm element. A detection target element is the upper arm element or the lower arm element to which the current detection elements are provided. A target duty is a duty ratio of the detection target element. The control unit includes a current acquisition unit, an energization control unit, and an abnormality determination unit. The current acquisition unit acquires a current detection value from the current detection unit. The abnormality determination unit performs an abnormality determination based on the current detection value. The abnormality determination unit varies a determination threshold, which is used for the abnormality determination based on the current detection value, according to the target duty.

Systems and methods for monitoring and suppressing a back EMF generated by an ESP motor when the ESP system is moved in a well. Embodiments provide both electrical braking to reduce the rotation of the motor (and corresponding back EMF) and warnings to alert users to hazardous conditions caused by the back EMF. One embodiment includes an ESP system having a permanent magnet motor, a back EMF safety system, and a power cable connected between them. The proximal ends of the cable's conductors are connected terminals of the back EMF safety system, which has switches that are closed to short circuit the conductors so that back EMF currents from rotation of the motor induce electrical braking in the motor. Currents and phase-to-phase voltages on the conductors are monitored to detect overcurrent and overvoltage conditions that may trigger alarms or other actions.

An electric motor has a mechanism to detect an overcurrent in an inverter circuit. The electric motor includes a rotor, a stator, and a board. The board includes a power transistor, a first resistor, a second resistor, and a constant voltage diode. The power transistor is included in the inverter circuit, which is configured to change a direction of a current that flows through a winding of the stator. The first resistor is provided between the power transistor and a ground terminal, and configured to detect an overcurrent in the inverter circuit. The second resistor is provided between the power transistor and the first resistor, and configured to detect a current that flows through the winding of the stator. The constant voltage diode is connected parallel to the first resistor.

A motor current protecting circuit is provided. A voltage calculating circuit determines whether or not each of low-side switches is fully turned on and then determines whether or not a voltage difference between a first terminal and a second terminal of each of the low-side switches being fully turned on is larger than or equal to a zero value. The voltage calculating circuit adds up the voltage differences each of which is larger than or equal to the zero value to output a voltage signal. A control circuit controls a driver circuit to switch the low-side switches and high-side switches according to the voltage signal.