A direct-current (DC) motor control device includes first and second switches, a conducting element and a power storage element. The power storage element, the conducting element and the second switch are connected to each other and form a loop, and the first switch is connected to a common node between the power storage element and the conducting element. When the DC electric power source is normally connected to the DC motor control device, the first switch is turned on, and the conducting element establishes a unidirectional conduction from a DC motor to the power storage element while the second switch is turned off.

An in-vehicle interrupting current supply device includes: a transformer that includes a first winding portion and a second winding portion; a driving unit; and a capacitor. The driving unit performs switching between a permission state in which current conduction to the first winding portion is permitted and a cancellation state in which the permission state is cancelled. The capacitor is electrically connected to an intermediate conductive path between the second winding portion and an interrupter, and can receive electric power from the second winding portion. In response to the driving unit repeating alternate switching between the permission state and the cancellation state, a charge current is supplied from the second winding portion side to the capacitor. The capacitor is discharged in response to a switch performing an ON operation, and a driving current flows into a current input portion.

The present disclosure provides a high-safety electric capstan including a hoisting mechanism, an electric motor configured to drive the hoisting mechanism to rotate, a user controller and an engagement assembly, and further including a control section electrically connected to a signal receiving actuator. The electric motor and the signal receiving actuator are electrically connected to the engagement assembly, respectively. The control section is configured for a user to send a trigger signal to the signal receiving actuator, the signal receiving actuator is configured to control an operation of the electric motor responsive to instructions from the user controller for a period of time when receiving the trigger signal, after the period of time, the signal receiving actuator is not responsive to instructions from the user controller. The solution of the present disclosure is advantageous for improving safety in use of an electric capstan.

The invention relates to a method for operating an electric machine (2) comprising a rotatably mounted rotor and a motor winding that is electrically connected to an electrical energy store (4) by means of a power electronics (3). In said method, the machine (2) and/or an apparatus comprising the machine (2) is/are monitored in respect of fault events, and the motor winding is short-circuited by triggering the power electronics (3) upon detection of a fault event. According to the invention, a desired trajectory (T) for an actual current vector (i.sub.actual,dq) of an electric motor current flowing through the motor winding is ascertained, said desired trajectory (T) extending from a current actual working point (AP1) of the machine (2) to a short-circuit working point (AP2) of the machine (2), a pilot control action is predicted according to the desired trajectory (T), and the power electronics (3) are triggered to short-circuit the motor winding according to the pilot control action in such a way that when the motor winding is short-circuited, a curve (V) of the actual current vector (i.sub.actual,dq) at least substantially matches the desired trajectory (T).

Some aspects of the present inventive concepts relate to a power conditioning unit for reduced-voltage soft starters (RVSS) in medium voltage motor control centers. The system mitigates issues caused by long shielded cables, such as high rates of current change (di/dt) and parasitic capacitance. The power conditioning unit, which can include a power factor correction capacitor (PFCC), a smoothing inductor, and a series fuse, may remain continuously connected in the circuit in some configurations. This setup can eliminate the need for a power conditioning unit capacitor contactor, thereby simplifying the operational complexity. The PFCC provides reactive power compensation, and has the potential to reduce voltage sag during high-slip start/stop events.