A variable-speed direct current motor comprising a stator (22), a rotor (23) arranged within the stator, and a motor drive device (40) arranged partly at the stator and partly at the rotor, wherein the stator comprises a yoke (25) defining a cylindrical cavity (31), and a plurality of permanent magnets (24) arranged at the yoke, wherein the rotor comprises a cylindrical core (26) and a conductor structure (47) arranged at the core, wherein the motor drive device comprises an alternating current transformer (41) having a primary winding (42) arranged at the stator and a secondary winding (43) arranged at the rotor, a rectifier device (44) arranged at the rotor and connected with the secondary winding, a direct current supply device (45) arranged at the rotor (23) and connected with the rectifier device (44), and with the conductor structure (47), and an operation control device (48) comprising a first unit (49) arranged at the rotor (23) and a second unit (50) arranged externally of the rotor and wirelessly communicating with the first unit.

A variable-speed direct current motor comprising a stator (22), a rotor (23) arranged within the stator, and a motor drive device (40) arranged partly at the stator and partly at the rotor, wherein the stator comprises a yoke (25) defining a cylindrical cavity (31), and a plurality of permanent magnets (24) arranged at the yoke, wherein the rotor comprises a cylindrical core (26) and a conductor structure (47) arranged at the core, wherein the motor drive device comprises an alternating current transformer (41) having a primary winding (42) arranged at the stator and a secondary winding (43) arranged at the rotor, a rectifier device (44) arranged at the rotor and connected with the secondary winding, a direct current supply device (45) arranged at the rotor (23) and connected with the rectifier device (44), and with the conductor structure (47), and an operation control device (48) comprising a first unit (49) arranged at the rotor (23) and a second unit (50) arranged externally of the rotor and wirelessly communicating with the first unit.

A variable-speed direct current motor comprising a stator (22), a rotor (23) arranged within the stator, and a motor drive device (40) arranged partly at the stator and partly at the rotor, wherein the stator comprises a yoke (25) defining a cylindrical cavity (31), and a plurality of permanent magnets (24) arranged at the yoke, wherein the rotor comprises a cylindrical core (26) and a conductor structure (47) arranged at the core, wherein the motor drive device comprises an alternating current transformer (41) having a primary winding (42) arranged at the stator and a secondary winding (43) arranged at the rotor, a rectifier device (44) arranged at the rotor and connected with the secondary winding, a direct current supply device (45) arranged at the rotor (23) and connected with the rectifier device (44), and with the conductor structure (47), and an operation control device (48) comprising a first unit (49) arranged at the rotor (23) and a second unit (50) arranged externally of the rotor and wirelessly communicating with the first unit.

To provide a power tool configured to stably rotate an end tool. The provided power tool includes a brushless motor including a rotor configured to rotate; a rectifier circuit configured to rectify an AC voltage; a smoothing capacitor configured to smooth the AC voltage rectified by the rectifier circuit to a pulsating voltage; an inverter circuit configured to perform switching operations to output the pulsating voltage to the brushless motor; a deceleration mechanism including: a driving portion at a rotor side, a driven portion configured to transmit a rotating force to an end tool side, and an elastic member configured to transmit a rotational force of the driving portion to the driven portion, the deceleration mechanism configured to decelerate a speed of a rotation of the rotor and configured to transmit the rotation to an end tool.

A permanent magnet alternator (PMA) includes a rotatable shaft, windings, a shunt regulator circuit, and a speed detection circuit. The rotatable shaft is connected electromagnetically to the windings. The shunt regulator circuit is electrically connected to the windings. A current sense transformer with a primary coil is electrically connected to the shunt regulator circuit. A secondary coil is electrically connected to a comparator circuit with reference voltage and generates voltage pulse indicating PMA speed. The voltage pulses form an output corresponding to and indicative of rotation speed of the shaft suitable for processing by a processor to present a PMA speed indication for use in the overall system architecture as a measurement parameter.

An integrated circuit for controlling operation of a motor of a fan assembly. The fan assembly includes a housing and a fan. The motor is in the housing. The housing is void of sensors. The motor is configured to rotate the fan. The integrated circuit includes a detection module and a first control module. The detection module is separate from the fan assembly. The detection module is configured to detect a voltage induced in a first coil of the motor or a back electromotive force received from the first coil of the motor. The first control module is configured to receive a control signal from a second control module and control the operation of the fan based on (a) the control signal, and (b) the voltage induced in the first coil of the motor or the back electromotive force. The second control module is separate from the integrated circuit.

An integrated circuit for controlling operation of a motor of a fan assembly. The fan assembly includes a housing and a fan. The motor is in the housing. The housing is void of sensors. The motor is configured to rotate the fan. The integrated circuit includes a detection module and a first control module. The detection module is separate from the fan assembly. The detection module is configured to detect a voltage induced in a first coil of the motor or a back electromotive force received from the first coil of the motor. The first control module is configured to receive a control signal from a second control module and control the operation of the fan based on (a) the control signal, and (b) the voltage induced in the first coil of the motor or the back electromotive force. The second control module is separate from the integrated circuit.

Methods and apparatus to control engine speed of a power system are disclosed. An example power system includes: an engine; an air compressor configured to generate and store air pressure in an air storage tank based on mechanical power provided by the engine; and control circuitry configured to: monitor the air pressure in the air storage tank; determine a rate of air pressure change based on the monitoring of the air pressure; in response to the rate of air pressure change satisfying a threshold rate, incrementally increasing a speed of the engine; detecting a load on an AC auxiliary output; and in response to detecting the load on the AC auxiliary output, overriding an engine speed based on the air compressor, and controlling the speed of the engine to be the predetermined speed to output the predetermined frequency.

Methods and apparatus to control engine speed of a power system are disclosed. An example power system includes: an engine; an air compressor configured to generate and store air pressure in an air storage tank based on mechanical power provided by the engine; and control circuitry configured to: monitor the air pressure in the air storage tank; determine a rate of air pressure change based on the monitoring of the air pressure; in response to the rate of air pressure change satisfying a threshold rate, incrementally increasing a speed of the engine; detecting a load on an AC auxiliary output; and in response to detecting the load on the AC auxiliary output, overriding an engine speed based on the air compressor, and controlling the speed of the engine to be the predetermined speed to output the predetermined frequency.

A permanent magnet alternator (PMA) includes a rotatable shaft, windings, a shunt regulator circuit, and a speed detection circuit. The rotatable shaft is connected electromagnetically to the windings. The shunt regulator circuit is electrically connected to the windings. A current sense transformer with a primary coil is electrically connected to the shunt regulator circuit. A secondary coil is electrically connected to a comparator circuit with reference voltage and generates voltage pulse indicating PMA speed. The voltage pulses form an output corresponding to and indicative of rotation speed of the shaft suitable for processing by a processor to present a PMA speed indication for use in the overall system architecture as a measurement parameter.