Various methods and systems are provided for a system for cooling an electric motor that includes a rotor shaft rotatably mounted inside a motor housing, a lamination stack integrally connected to the rotor shaft, an encoder-end balance plate integrally connected to a first end of the lamination stack and a first end of the rotor shaft, an output-end balance plate integrally connected to a second end of the lamination stack and a second end of the rotor shaft, an oil supply coupled to the output-end balance plate and the rotor shaft. A closed-looped coolant pathway is formed between the transmission, the rotor shaft, the encoder-end balance plate, the lamination stack, and the output-end balance plate.

A dual-voltage brushless motor (30) includes a casing, a motor shaft (20) rotatably coupled to the casing, a rotor fixedly connected to the motor shaft (20), and a stator (28) configured to face the motor. The rotor contains a plurality of permanent magnets, and the stator (28) includes a first set of winding and a second set of winding. The first winding is electrically isolated from the second winding. The dual-voltage brushless motor (30) is adapted to be driven when the first set of winding receives a first control signal or when the second set of winding receives a second control signal. By configuring two separate motor controllers of the motor, the motor (30) can be operated under different power supplies such as AC power supply and DC power supply. As a result the application of the motor is greatly extended.

A dual-voltage brushless motor (30) includes a casing, a motor shaft (20) rotatably coupled to the casing, a rotor fixedly connected to the motor shaft (20), and a stator (28) configured to face the motor. The rotor contains a plurality of permanent magnets, and the stator (28) includes a first set of winding and a second set of winding. The first winding is electrically isolated from the second winding. The dual-voltage brushless motor (30) is adapted to be driven when the first set of winding receives a first control signal or when the second set of winding receives a second control signal. By configuring two separate motor controllers of the motor, the motor (30) can be operated under different power supplies such as AC power supply and DC power supply. As a result the application of the motor is greatly extended.

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.

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 rotating machine has a first end frame and a second end frame for firmly supporting a stator between them in an axial direction of the electric rotating machine. An electronic control portion is mounted to a rear side of the first end frame. Multiple through-holes are formed at a radial-outer periphery of the second end frame. Each of multiple through-bolts is inserted into the respective through-holes from a side of the second end frame and screwed into the first end frame, to thereby firmly connect the first and the second end frames to each other.

An apparatus including a frame, an optical sensor connected to the frame, and an environment separation barrier. The frame is configured to be attached to a housing of a motor assembly proximate an aperture which extends through the housing. The optical sensor comprises a camera. The environment separation barrier is configured to be connected to the housing at the aperture, where the environment separation barrier is at least partially transparent and located relative to the camera to allow the camera to view an image inside the housing through the environment separation barrier and the aperture.

An apparatus including a frame, an optical sensor connected to the frame, and an environment separation barrier. The frame is configured to be attached to a housing of a motor assembly proximate an aperture which extends through the housing. The optical sensor comprises a camera. The environment separation barrier is configured to be connected to the housing at the aperture, where the environment separation barrier is at least partially transparent and located relative to the camera to allow the camera to view an image inside the housing through the environment separation barrier and the aperture.

An adapter is used to couple a prime mover body to a housing of a generator. The adapter has openings that allow an armature of the generator to be attached to the flywheel of the prime mover. The adapter provides a torque coupling between the prime mover and the generator so that the attachments of the prime mover and generator to the skid, as well as the skid itself, can be reduced in size and weight because they no longer need to oppose the prime mover-generator torque load. A thickness of the adapter and a pattern of the openings in the body of the adapter are selected to move any natural resonance frequencies of the adapter outside an operating frequency of the prime mover.

An assembly for generating electricity includes a circular track configured to rotate about a first axis of rotation, the circular track comprising a first magnet having a face that is at an angle with respect to the first axis of rotation, a second magnet positioned at a center of the circular track, wherein a face of the second magnet is an opposite polarity to the face of the first magnet such that the second magnet repels the first magnet to rotate the circular track, and a device for converting rotational motion from the circular track into electricity.