Selectable current limiting for a power tool. One embodiment provides a method for selectable current limiting for a power tool including determining, using a current sensor, an average current and determining whether the average current exceeds a predetermined current threshold. The method also includes determining a deviation of the average current from the predetermined current threshold and reducing a PWM duty ratio proportional to the deviation of the average current from the predetermined current threshold. The PWM duty ratio corresponds to a PWM signal provided to an inverter bridge.

An electric motor may comprise a rotor and a stator comprising rotor and stator teeth, respectively. A non-uniform angular spacing or grouping of rotor teeth may facilitate desired rotational speeds of the rotor.

An electronic switch module for a power tool is provided including a housing, a trigger moveable relative to the housing, a magnet being moveable relative to the housing with the trigger along a movement axis, and a linear hall sensor fixed relative to the housing 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 housing, a trigger moveable relative to the housing, a magnet being moveable relative to the housing with the trigger along a movement axis, and a linear hall sensor fixed relative to the housing 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 of operating a heating, ventilation, and air conditioning (HVAC) system including: transmitting, using an equipment control board, an operation request in a pulse width modulation (PWM) signal to an electronically commutate motor (ECM) controller of a blower motor, wherein the operation request includes a switching period command configured to vary a switching period of the PWM signal; operating the blower motor in accordance with the operation request by varying the switching period of the PWM signal; detecting a parameter of the blower motor for each of a plurality of switching periods as the switching period varies; and mapping the parameter of the blower motor for each of the plurality of switching periods.

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.

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.

A hand-held power tool includes an electronically commutated motor including a motor winding. Motor electronics of the hand-held power tool are configured to electronically commutate the motor winding using a selected one of a plurality of electrical precontrol angles, thereby adapting the motor winding to different mechanical load conditions of the electronically commutated motor.

A hand-held power tool includes an electronically commutated motor including a motor winding. Motor electronics of the hand-held power tool are configured to electronically commutate the motor winding using a selected one of a plurality of electrical precontrol angles, thereby adapting the motor winding to different mechanical load conditions of the electronically commutated motor.

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.