A power tool includes a control for the motor of the power tool that senses an operating characteristic of the motor and controls the operation of the power tool based on the sensed characteristic. The sensed characteristic includes variations in reluctance of the motor. A controller may sense changes on load on the motor as a result of interaction between a working element such as a saw blade or drill bit and the work piece. The controlled operation may include variation in speed or torque or both, or may include stopping the motor. Emergency conditions may be sensed by changes in reluctance.

A power tool includes a control for the motor of the power tool that senses an operating characteristic of the motor and controls the operation of the power tool based on the sensed characteristic. The sensed characteristic includes variations in reluctance of the motor. A controller may sense changes on load on the motor as a result of interaction between a working element such as a saw blade or drill bit and the work piece. The controlled operation may include variation in speed or torque or both, or may include stopping the motor. Emergency conditions may be sensed by changes in reluctance.

A power tool includes a control for the motor of the power tool that senses an operating characteristic of the motor and controls the operation of the power tool based on the sensed characteristic. The sensed characteristic includes variations in reluctance of the motor. A controller may sense changes on load on the motor as a result of interaction between a working element such as a saw blade or drill bit and the work piece. The controlled operation may include variation in speed or torque or both, or may include stopping the motor. Emergency conditions may be sensed by changes in reluctance.

A power tool includes a housing, a motor, an output member driven by the motor, and a reaming attachment coupled to the output member. The reaming attachment has a front end portion selectively driven in rotation by the output member to drive a fastener into a workpiece, and a reaming portion selectively driven in rotation by the output member to remove material from an end surface of a conduit. A rotational motion sensor in the housing is operable to detect rotational motion of the housing about an axis. A controller receives a signal indicative of rotational motion from the sensor, determines a direction of the rotational motion of the housing, and drives the motor in a direction corresponding to the direction of rotational motion of the housing.

A method to control a power tool includes the following steps: ascertaining a first rotational speed of the transmission in a first gear; ascertaining a first rotational speed of the motor when the transmission has been put into a first gear; ascertaining the selection of a first gear on the basis of the ratio of the rotational speed of the transmission and the rotational speed of the motor on the basis of a look-up table; selecting the no-load state; ascertaining the selected no-load state on the basis of the ratio of the rotational speed of the transmission and the rotational speed of the motor on the basis of a look-up table; adapting the rotational speed of the motor to a second gear on the basis of a ratio of the rotational speed of the transmission and the rotational speed of the motor on the basis of a look-up table; and selecting a second gear.

A power tool includes a control for the motor of the power tool that senses an operating characteristic of the motor and controls the operation of the power tool based on the sensed characteristic. The sensed characteristic includes variations in reluctance of the motor. A controller may sense changes on load on the motor as a result of interaction between a working element such as a saw blade or drill bit and the work piece. The controlled operation may include variation in speed or torque or both, or may include stopping the motor. Emergency conditions may be sensed by changes in reluctance.

A method to control a power tool includes the following steps: ascertaining a first rotational speed of the transmission in a first gear; ascertaining a first rotational speed of the motor when the transmission has been put into a first gear; ascertaining the selection of a first gear on the basis of the ratio of the rotational speed of the transmission and the rotational speed of the motor on the basis of a look-up table; selecting the no-load state; ascertaining the selected no-load state on the basis of the ratio of the rotational speed of the transmission and the rotational speed of the motor on the basis of a look-up table; adapting the rotational speed of the motor to a second gear on the basis of a ratio of the rotational speed of the transmission and the rotational speed of the motor on the basis of a look-up table; and selecting a second gear.