The invention relates to a method for operating a power tool, according to which a measuring device determines a winding resistance (R.sub.S) of a winding of an electric motor of the power tool. A test signal source applies a test signal (i.sub.p) to the winding during operation of the electric motor, a measuring unit records at least one measured value (U.sub.d, i.sub.d) as a reaction of the winding to the test signal (i.sub.p), and a control device determines the winding resistance (R.sub.S) while taking into consideration the measured value (U.sub.d, i.sub.d).

The present disclosure relates to a method for motor thermal overload protection, including: obtaining a motor thermal limit curve; selecting a first and a second overload factor calculation point on the curve, and calculating the first and second overload factors based on a preset heating time constant; calculating a modified overload factor based on the first and second overload factors; selecting at least two time constant calculation points on the motor thermal limit curve, and calculating a modified heating time constant for each time constant calculation point based on the modified overload factor; obtaining a modified heating time function for each motor operating point based on the modified heating time constant for each time constant calculation point; calculating a stator heat level at each motor operating point based on the modified overload factor and heating time function; comparing the stator heat level with the first and second predetermined thresholds.

Examples described herein provide a computer-implemented method that includes monitoring, using a microcontroller, an electric circuit of a vehicle, the electric comprising a battery source and a load. The battery source supplies electric power to the load. The method further includes detecting, using the microcontroller, a high current event in the electric circuit by comparing a current level of a current flowing through the electric circuit to a time-based current threshold. The method further includes responsive to detecting the high current event, controlling a gate driver to cause a switch of an electronically resettable fuse to open the electric circuit to stop the flow of the current through the electric circuit.

A thermal monitoring system includes thermal monitoring devices that generate sensor data including thermal images depicting monitored elements (e.g. of an electrical switchgear system). The sensor data for all monitoring devices installed at a local deployment is collected by a gateway device, and relevant data from multiple local deployments is further aggregated by a cloud management system for further analysis. New event triggering rules determining how the thermal monitoring devices filter or record the sensor data are generated based on the aggregated data during a continuous learning process. The system detects patterns in the sensor data for the monitoring devices and/or local deployments as a whole and tracks deviations from these patterns, improving the accuracy of the event detection over time.

An embodiment electronic circuit includes an electronic switch comprising a load path, and a control circuit configured to drive the electronic switch. The control circuit is configured to operate in one of a first operation mode and a second operation mode based at least on a level of a load current of the electronic switch. In the first operation mode the control circuit is configured to generate a first protection signal based on a current-time-characteristic of the load current and drive the electronic switch based on the first protection signal. The control circuit is configured to generate a status signal such that the status signal has a wakeup pulse when the operation mode changes from the second operation mode to the first operation mode and, after the wakeup pulse, a signal level representing a level of the load current.

An electric-wire protection device that protects an electric wire by cutting off power to the wire when its temperature is elevated above a predetermined value is presented. The device includes switching means to control the conduction of power to the wire, current measuring means to measure a current in the wire, environment temperature detecting means to detect a temperature of the environment surrounding the wire, electric-wire temperature calculating means to calculate the temperature of the wire using the value of the current in the wire and the environment temperature, limiting means to stop the conduction of power to the wire when the temperature is greater than or equal to a predetermined value, peripheral component current measuring means to measure the current flowing to a component at the periphery of the environment temperature detecting means, thermal influence acquisition means to obtains an amount of temperature increase caused by the component at the environment temperature detecting means, and environment temperature correcting means to correct the environment temperature based on the amount of temperature increase.

A monitoring method for an electrical energy transfer device which has a first phase conductor and a second phase conductor, includes the following steps: a temperature of the first phase conductor is compared with the temperature of the second phase conductor and a signaling is performed if there is a deviation between the temperatures. The electrical energy transfer device is, for this purpose, equipped at the first phase conductor with a first temperature sensor and at the second phase conductor with a second temperature sensor.

A power supply system includes: a battery; a master device supplied with power from the battery; and a slave device supplied with power from the master device via a first power supply line. The slave device supplies power to a load via a second power supply line. The master device estimates a temperature of the second power supply line. When the estimated temperature of the second power supply line is higher than a second cutoff threshold, power supply via the second power supply line is cut off.

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.

Systems and methods for providing information about thermal overload conditions and near-miss tripping events in a circuit interrupter are disclosed. The systems and methods provide a user with detailed information about thermal overload and near-miss tripping events, including how much time remains until a trip will be initiated due to a thermal overload, and what the real-time thermal capacity of the circuit interrupter is after a thermal overload condition ends.