An exciter circuit for an externally excited synchronous machine, wherein the exciter circuit comprises power supply terminals connectable to a current source, exciter current terminals connectable to a rotor winding of a rotor of the synchronous machine, and a protection circuit which, in operation, connects conductively the power supply terminals when a triggering condition is fulfilled.

A converter apparatus includes: an AC/DC converter; a DC link capacitor connected to the converter; a voltage detection unit detecting the DC link voltage; a switching unit connecting or disconnecting between a power supply and the converter; a switching operation unit detecting an abnormality in a motor drive device including the converter apparatus and an inverter, and control the switching unit; a power supply monitoring unit detecting a voltage inputted to the converter to monitor a connection state between the power supply and the converter; a threshold value setting unit setting a threshold value to determine the presence or absence of a short circuit failure; and a short circuit failure detection unit determining that a short circuit failure has occurred, when the voltage of the DC link capacitor, immediately after the power supply is disconnected from the converter, is equal to or less than the threshold value.

A safety device includes a safety module and a safety control module in order to reduce a speed of an unwanted clutch engagement when a malfunction of a motor for a clutch control actuator occurs, such as by the power supply for the motor being interrupted, so that a driver can have more time to react in such situation.

Methods and systems for operating a hybrid electric aircraft propulsion system. The method comprises providing alternating current (AC) electric power to a first electric motor to drive a first rotating propulsor, providing the first electric motor with AC electric power from at least one motor inverter operatively coupled to a direct current (DC) power source, detecting a failure in a path to the first electric motor, and selectively rearranging a first switching arrangement between the generator, the at least one motor inverter, and the first electric motor.

A method and a device for bringing a textile machine to a controlled standstill in the event of a failure of the power supply, and a correspondingly equipped textile machine, the textile machine having at least two axes that are driven in synchronization by respective electric motors (M.sub.1-M.sub.5) connected to a common intermediate voltage circuit (1), and in which at least one electric motor acting as power generator can supply electric power to at least one other electric motor via the common DC bus (1), and in which the voltage (V) on the common DC bus is controlled by varying at least two variables in such a way that the voltage follows a previously defined curve while the textile machine is being brought to a standstill.

A motor drive circuit for driving an electric motor includes a plurality of driver circuits, each one of the plurality of driver circuit comprising a high side transistor coupled to a low side transistor in a half bridge arrangement, wherein each one of the high side transistors and each one of the low side transistors has a respective control node and respective first and second current passing nodes, wherein the second current passing node of each of the high side transistors is coupled to the first current passing node of a respective one of the low side transistors at a respective junction node, wherein each one of the plurality of driver circuits is operable to drive a respective current out of a respective junction node into a respective winding of the electric motor. The motor drive circuit further includes a capacitor coupled to the first current passing node of each one of the high side transistors, the capacitor operable to hold a capacitor voltage. The motor drive circuit further includes a power loss brake control circuit coupled to receive the capacitor voltage from the capacitor and operable to sense when a power supply voltage to the motor drive circuit is below a threshold voltage and, in a braking mode of operation, the high side transistors are off, and also in the braking mode of operation, when the power supply voltage is below the threshold voltage, the power loss brake control circuit is operable to generate at least one pulse signal having at least two state transitions and operable to communicate the at least one pulse signal to a respective at least one of the control nodes of a respective at least one of the low side transistors, resulting in on and off conditions of the at least one of the low side transistors, wherein the on condition of the at least one of the low side transistors results in the braking mode of operation during the on condition, and wherein the at least two state transitions results in a voltage boosting operation such that the capacitor voltage is a boosted voltage, the boosted voltage higher than a voltage that would be achieved without the at least two state transitions.

In a power source system, a high-voltage battery and a low voltage battery are configured to store electric powers to be supplied to a traveling motor and an accessory, respectively. A step-up unit is interposed between the low-voltage battery and the traveling motor, and is configured to step up a voltage of the low-voltage battery and apply the stepped-up voltage to the traveling motor. A controller is configured to perform switching to a normal-time electric power supply circuit, in which the high-voltage battery and the traveling motor are coupled to each other, when the high-voltage battery is in a normal state and perform switching to an abnormal-time electric power supply circuit, in which the low-voltage battery and the traveling motor are coupled to each other via the step-up unit, when the high-voltage battery is in an abnormal state.

An object of the present invention is to improve reliability after the control of a microcomputer recovers. A signal control apparatus according to the present invention includes a microcomputer, an output control unit that receives a reset signal and a load control signal from the microcomputer and outputs a load output signal to a load, and when the output control unit receives the reset signal, the output control unit maintains a state of the load output signal immediately before the reset signal is received, and when the load control signal is switched, the output control unit releases the maintaining state of the load output signal.

A drive device capable of recording a working status includes: a drive mechanism, including a housing, an actuating unit configured inside the housing and a transmission unit configured inside the housing and in connection with the actuating unit; a sensing unit, configured inside the housing and in electric connection with the actuating unit; and a storage unit, configured inside the housing and in electric connection with the sensing unit. Whereby, the drive device can be installed inside a unmanned control or automatic machine, utilizes the sensing unit to sense a working status of the drive mechanism, and records working status data in the storage unit; the working status stored in the storage unit can be read after the machine fails or is damaged, the working status of the drive mechanism of the damaged machine, and the cause of the failure occurrence is clarified, as a basis for subsequent performance improvement.

A method and a device for bringing a textile machine to a controlled standstill in the event of a failure of the power supply, and a correspondingly equipped textile machine, the textile machine having at least two axes that are driven in synchronization by respective electric motors (M1-M.sub.5) connected to a common intermediate voltage circuit (1), and in which at least one electric motor acting as power generator can supply electric power to at least one other electric motor via the common DC bus (1), and in which the voltage (V) on the common DC bus is controlled by varying at least two variables in such a way that the voltage follows a previously defined curve while the textile machine is being brought to a standstill.