A load protection system and a method of protecting a load. The load protection system includes a PLC transmitter module and a PLC receiver module, which are configured to communicate a plurality of bits of data, each bit transmitted near a zero-crossing of a voltage on the power lines supplying power to the load, in the form of a high frequency burst of pulses. The pulses are structured in two patterns. The first pattern serves to identify the start of the second pattern, and the second pattern includes the data. The first pattern is unique and not represented within the second pattern. The load may be a motor, and the data may include a parameter value representing a parameter of the motor.

According to an aspect of the present invention, an electric working machine is provided. The electric working machine comprises a motor, an operation portion, a working portion, and a controller. The working portion is configured to be driven by the motor and act on a work target. The operation portion is configured to be operated by an operator. The controller is configured to control a maximum power that can be input to the motor to a first power when receiving an operation signal indicating an amount of operation to the operation portion. Further, the controller is configured to perform first switching control to switch the maximum power to a second power that is less than the first power when rotation speed of the motor becomes less than a first threshold due to a load on the working portion.

A disconnect system to be connected between a DC power source formed by the battery system of a vehicle and a load of the vehicle comprises at least one relay switch and at least one thermostat switch. The at least one relay switch is electrically connected between the DC power source and the load to form a power circuit. The at least one thermostat switch is secured to a sensed portion of the load. The at least one thermostat switch is connected to the at least one relay switch to form a control circuit. The at least one relay switch is closed when current flows through the control circuit. When a temperature of the at least one thermostat switch reaches a predetermined temperature level, the at least one thermostat switch prevents current from flowing through the control circuit.

A protection device provided between a synchronous motor having a plurality of windings and a motor driving device for driving the synchronous motor includes: a switching unit for making and breaking the connection between the motor driving device and the synchronous motor; a dynamic brake circuit including resistors and switches, to short-circuit the plurality of windings between the switching unit and the synchronous motor via the resistors; and a control device for controlling the switching unit and the dynamic brake circuit. The control device controls the switches in the dynamic brake circuit to short-circuit the plurality of windings, and then controls the switching unit to cut off the connection between the motor driving device and the synchronous motor.

The present disclosure provides a protection apparatus for a galvanometer laser system, including a system constituted by a galvanometer motor and a laser, wherein the apparatus further includes a protection device, the protection device including a monitoring element and a control element; wherein the monitoring element includes a current monitoring module configured to monitor an operating current of the system, a position monitoring module configured to monitor a swing position of the galvanometer motor, and a temperature monitoring module configured to monitor an operating temperature of the galvanometer motor; the control element includes a signal control module connected to a signal input terminal of the system, a laser switch module connected to the laser, and a galvanometer drive module connected to the galvanometer motor, a predetermined output signal being transmitted via the signal control module to the system; and based on various monitoring data of the monitoring element.

A starter motor connected to a power supply and operable to start an internal combustion engine includes an outer housing and a solid state switching device associated with the outer housing. The outer housing encloses a commutator and a series of brushes. The solid state switching device is movable between an open position and a closed position. The current flow from the power supply through the commutator is prevented when the solid state switching device is in the open position.

A compact electric motor (1) includes a housing (2), a stator (3), a rotor (4) with a rotor winding (5) or permanent magnets located thereon. A thermal protection device protects the electric motor against overheating. A sensor unit (6) is provided as a thermal protection device. The sensor unit (6) includes a temperature sensor (7) for detecting temperature-based measurement values, a radio module (8) with an antenna (8a) for sending sensor signals of temperature-based measurement values or data or information derived therefrom by radio to an external receiving unit (9). The sensor unit (6) has a memory (13) and a microcontroller (10). The sensor unit (6) is a self-supplying assembly.

A hand-held machine tool, in particular a sanding machine, including a handle element for the user to grip and a processing head which has an electric drive motor for driving a tool holder provided for holding a processing tool, the hand-held machine tool having a power supply system for supplying power to the drive motor by means of a cable arrangement, via which the drive motor and the power supply system are interconnected. A protection circuit including at least one electric disconnector is arranged on the drive motor, in order to disconnect a connection between at least one electric cable of the cable arrangement and a phase of a field coil arrangement of the drive motor, which phase can be supplied with current via the cable.

Provided are a method and apparatus for determining motor temperature, and a storage medium. The method includes: obtaining an electromagnetic loss of each node in ξ nodes acquired by decomposing components of a motor, wherein the ξ is a natural number greater than 1, and at least one component in the components of the motor is decomposed into multiple nodes in the ξ nodes; obtaining a thermal resistance between every two nodes in the ξ nodes; and determining a temperature of the motor based on the electromagnetic loss of the each node in the ξ nodes and the thermal resistance between the every two nodes in the ξ nodes.

It is disclosed a motor thermal protection device and operation method thereof. The motor thermal protection device utilizes a power supply of a motor for power supplying and comprises: a capacitor timing circuit, configured to time after the motor is powered off; a power-off time determining unit, configured to perform a reading operation of reading an output voltage of the capacitor timing circuit after the motor is powered on, and determine a power-off time from when the motor is powered off to when the motor is powered on according to the output voltage; and a heat accumulation calculating unit, configured to calculate a remaining heat accumulation when the motor is powered on according to the power-off time and a heat accumulation when the motor is powered off.