A method of adaptively controlling a brushless DC motor includes steps of: controlling the brushless DC motor rotating at a first speed according to an operation curve, accumulating a running time of the brushless DC motor, estimating a remaining used time of a bearing of the brushless DC motor according to the accumulated running time, executing an alarm operation when the remaining used time is less than a predetermined time, and decreasing the speed of the brushless DC motor to run at a second speed to prolong the used time of the bearing.

A current measuring system (10) for a commutated motor (20). The current measuring system comprises a bridge circuit (30) with several branches (30a-c), wherein the branches (30a-c) are in each case connected to commutation blocks of the commutated motor (20), and the branches (30a-c) each have a current measuring circuit (60a-c).

A current measuring system (10) for a commutated motor (20). The current measuring system comprises a bridge circuit (30) with several branches (30a-c), wherein the branches (30a-c) are in each case connected to commutation blocks of the commutated motor (20), and the branches (30a-c) each have a current measuring circuit (60a-c).

An electronic switch module for a power tool is provided including a module body, a trigger moveable relative to the module body, a magnet being moveable relative to the module body with the trigger along a movement axis, and a linear Hall sensor fixed relative to the module body and intersecting the movement axis of the magnet. The linear Hall sensor magnetically detects a linear position of the magnet along the movement axis and outputs a voltage signal based on the detected linear position.

An electronic switch module for a power tool is provided including a module body, a trigger moveable relative to the module body, a magnet being moveable relative to the module body with the trigger along a movement axis, and a linear Hall sensor fixed relative to the module body and intersecting the movement axis of the magnet. The linear Hall sensor magnetically detects a linear position of the magnet along the movement axis and outputs a voltage signal based on the detected linear position.

A method for determining a direction of rotation for an electronically commutated motor (ECM) is described. The motor is configured to rotate a blower and the method comprises rotating the blower using the ECM and determining if the resulting blower rotation is indicative of the desired direction of rotation for the blower.

An electronic module is provided including power switches mounted on a circuit board and configured as an inverter circuit for an electric motor. A sliding member is coupled to an actuator. A power contact switch is provided including a first conductive body, a second conductive body, and a contact switch. The first and second conductive bodies are mounted on a first surface of the circuit board and include pins received through through-holes of the circuit board to make electrical contact with two conductive tracks on a second surface of the circuit board. The contact switch pivotably is secured to the first conductive body and pivotably moveable by the sliding member to make contact with the second conductive body with movement of the actuator. A flyback diode is electrically connected between the first and second conductive track on the second surface of the circuit board parallel to the power contact switch.

An electronic module is provided including power switches mounted on a circuit board and configured as an inverter circuit for an electric motor. A sliding member is coupled to an actuator. A power contact switch is provided including a first conductive body, a second conductive body, and a contact switch. The first and second conductive bodies are mounted on a first surface of the circuit board and include pins received through through-holes of the circuit board to make electrical contact with two conductive tracks on a second surface of the circuit board. The contact switch pivotably is secured to the first conductive body and pivotably moveable by the sliding member to make contact with the second conductive body with movement of the actuator. A flyback diode is electrically connected between the first and second conductive track on the second surface of the circuit board parallel to the power contact switch.

A BLDC motor driver circuit includes: a driving power stage circuit configured to provide a start-up test signal in a start-up mode to excite a BLDC motor, to drive a rotor of the BLDC motor to rotate for a test; a current unidirectional circuit coupled to the BLDC motor at a reverse end for detecting a BEMF, to generate a detection signal at a forward end of the current unidirectional circuit, wherein when a voltage at the reverse end exceeds a voltage at the forward end, the current unidirectional circuit limits the voltage at the forward end not to be higher than a clamp voltage; a biasing circuit for biasing the current unidirectional circuit in a forward operation state and for providing the clamp voltage; and a sensor circuit for generating a sensing signal according to the detection signal to indicate a test rotation state of the BLDC motor.

A system is for a machine having an alternating current (AC) power source with a first side and a second side, one or more windings, an AC polarity detector, a Hall effect device, two or more pairs of power switches, and a motor controller. The motor controller determines which of the power switches to open or close to obtain a direction of current flow through the one or more windings based on signals from the AC polarity detector and the Hall effect device.