A protective redundancy circuit is provided for a power tool having an electric motor. The protective redundant subsystem is comprised of: a motor switch coupled in series with the motor; a motor control module that controls the switching operation of the motor switch; and a protective control module that monitors switching operation of the motor switch and disables the power tool when the switching operation of the motor switch fails. In the context of an AC powered tool, the switching operation of the motor switch is correlated to and synchronized to the waveform of the AC input signal. During each cycle or half cycle, the motor control module introduces a delay period before closing the motor switch and the protective control module determines the operational status of the motor switch by measuring the voltage across the motor switch during the delay period.

A switching power supply device has a switching output stage generating an output voltage from an input voltage by switching operation and a controller controlling the switching output stage based on a feedback voltage commensurate with the output voltage. The switching power supply device can perform switching suspension control whereby it stops switching operation on detecting a light-load condition based on the feedback voltage, though it restarts switching operation on detection of an overvoltage condition during suspension of switching operation.

An electric oil pump includes a control substrate including a reverse connection protection circuit to protect a circuit in the substrate, a first substrate wiring connected to a source terminal of a MOSFET in the reverse connection protection circuit, a second substrate wiring connected to a GND terminal, and a bypass circuit that causes a current to flow from the first substrate wiring to the second substrate wiring in a case in which an output voltage of the external power supply is equal to or greater than a predetermined value that is greater than a rated voltage, in which the predetermined value is a value that is smaller than a withstanding voltage between a gate and the source of the MOSFET.

A switching power supply device has a switching output stage generating an output voltage from an input voltage by switching operation and a controller controlling the switching output stage based on a feedback voltage commensurate with the output voltage. The switching power supply device can perform switching suspension control whereby it stops switching operation on detecting a light-load condition based on the feedback voltage, though it restarts switching operation on detection of an overvoltage condition during suspension of switching operation.

Embodiments of this application disclose a control circuit of a galvanometer motor and a LiDAR. The control circuit is configured to control the galvanometer motor to be discharged during a power failure, and the control circuit includes a switch circuit and a discharge circuit. The switch circuit is configured to access a control voltage; and the discharge circuit is connected to the switch circuit and configured to be connected to a driving positive electrode and a driving negative electrode of the galvanometer motor.

A power tool includes a motor and control means for controlling the motor. The motor is capable of being driven by power supplied from a battery pack including a battery cell. The control means is configured to continue to rotate the motor even when a motor-halt signal is inputted from the battery pack. With this structure, the power tool can be used continuously without need to halt rotation of the motor, even when receiving a halt signal, such as an overdischarge detection signal or an overcurrent detection signal.

A power tool includes a motor and control means for controlling the motor. The motor is capable of being driven by power supplied from a battery pack including a battery cell. The control means is configured to continue to rotate the motor even when a motor-halt signal is inputted from the battery pack. With this structure, the power tool can be used continuously without need to halt rotation of the motor, even when receiving a halt signal, such as an overdischarge detection signal or an overcurrent detection signal.

Exemplary embodiments are disclosed of a relay control or contactor configured to provide adaptive undervoltage protection for a three-phase load using a single current sensor. The current sensor is electrically connected with a corresponding one of a first, second, or third relay for providing information about current from the corresponding relay to a load. The information may be usable to determine a failure condition when: after the relays are energized, the information indicates that: there is no current across the corresponding one of the first, second, and third relays thereby indicating that the corresponding one of the first, second, and third relays is open and the load is running on two phases; or the current across the corresponding one of the first, second, and third relays is at lock rotor current for more than a determined amount of time indicating that the load is running on two phases.

A connection system for connecting a work machine to an external large-capacity energy source includes an electrically conductive member configured to provide electrical energy from the external energy source to an energy receptacle of the work machine; a first contactor mechanically movable between a closed position electrically connecting the external energy source and the electrically conductive member, and an open position physically disconnecting the external energy source and the electrically conductive member; a second contactor mechanically movable between a closed position electrically connecting the electrically conductive member and the energy receptacle, and an open position physically disconnecting the electrically conductive member and the energy receptacle; and controller configured to receive an indication to disconnect the electrical power system of the work machine from the external energy source; and selectively initiate opening of the first contactor or the second contactor according to the received indication.