An electrical machine comprising: at least one stator, at least one module, the at least one module comprising at least one electromagnetic coil and at least one switch, the at least one module being attached to the at least one stator; at least one rotor with a plurality of magnets attached to the at least one rotor, an integrated electrical differential coupled to at least one of the rotors, the at least one integrated electrical differential permitting the at least one rotor to output at least two rotational outputs to corresponding shafts, wherein the at least two rotational outputs are able to move the shafts at different rotational velocities to one another. The electrical machine is configured to fit into a housing, and that can be retrofitted into a conventional vehicle by replacing the mechanical differential.

An electrical machine comprising: at least one stator, at least one module, the at least one module comprising at least one electromagnetic coil and at least one switch, the at least one module being attached to the at least one stator; at least one rotor with a plurality of magnets attached to the at least one rotor, an integrated electrical differential coupled to at least one of the rotors, the at least one integrated electrical differential permitting the at least one rotor to output at least two rotational outputs to corresponding shafts, wherein the at least two rotational outputs are able to move the shafts at different rotational velocities to one another. The electrical machine is configured to fit into a housing, and that can be retrofitted into a conventional vehicle by replacing the mechanical differential.

A method for preventing motion of an output shaft (401), of an electromagnetic motor comprising a coil assembly, when a mechanical brake (400) is released, comprising the steps of: determining the position of the output shaft (401); correlating the position of the output shaft (401) with a current such that when applied in the coil assembly induces a force on the output shaft (401) to prevent motion of the output shaft (401) when the mechanical brake (400) is released.

A mechanical brake for arresting movement of the output shaft of a linear electric motor, comprising a pivotally mounted plate having a space for receiving the output shaft of the motor; an electrically operated holding device contacting a free end of the plate and arranged to hold the plate in a condition to permit movement of the output shaft and to permit the plate to pivot to a jamming position; wherein the electrically operated holding device comprises a solenoid to control the movement of the plate.

A modular motor drive for use in fitness equipment includes a switching circuit having switches and that is responsive to switching control signals by selectively reconfiguring the switches to control supply of electrical energy to a motor of an exercise device according to the switching control signals. The motor drive further includes an interface coupleable with an application control board of the exercise device. Responsive to a first switching control signal, the switching circuit configures the plurality of switches to drive the motor of the exercise device. Responsive to a second switching control signal corresponding to electric braking of the motor, the switching circuit configures the plurality of switches to stop driving the motor of the exercise device.

A technique facilitates a fracturing operation in a borehole and surrounding formation. The technique utilizes braking to arrest the rotation of an electric frac system and to thus limit the magnitude of a pressure peak in the event of an over-pressure shut down or other type of emergency shutdown. According to an embodiment, an electric motor is coupled with a fracturing pump which may be operated to pump a fracturing fluid into a well. Stopping or otherwise braking of the electric frac system is facilitated by applying rotor drag to a rotor of the electric motor.

A technique facilitates a fracturing operation in a borehole and surrounding formation. The technique utilizes braking to arrest the rotation of an electric frac system and to thus limit the magnitude of a pressure peak in the event of an over-pressure shut down or other type of emergency shutdown. According to an embodiment, an electric motor is coupled with a fracturing pump which may be operated to pump a fracturing fluid into a well. Stopping or otherwise braking of the electric frac system is facilitated by applying rotor drag to a rotor of the electric motor.

Embodiments are disclosed for the control of downhole pumping systems that can perform a controlled draining operation of the downhole pumping system in the event of an interruption of a drive. Such embodiments include a zero power factor control, a motor braking, and a pumping down operation. The apparatus and the methods disclosed can include an independent piece of equipment interlocked with a variable speed drive, and installed at the primary or secondary of the step-up transformer where used. However, integration within other pieces of equipment, in particular the variable speed drive, and its control by the latter is also contemplated. Also disclosed is a transformer having a tap changer that includes a plurality of taps and contacts including shorting contacts, open contacts and auxiliary contacts.

An electric motor control device controls driving of electric motors connected in parallel with each other and includes a power converter converting power from a power supply, and supply the converted power to each of the electric motors, a switching device to be turned on to electrically connect the power converter and at least one of the electric motors and to be turned off to electrically disconnect the power converter and the at least one of the electric motors, a current detection unit detecting a current that flows in the electric motors, and a controller controlling the power converter on the basis of operation of the switching device, rotation frequency command values from an external device, and a value of the current detected by the current detection unit. The controller turns the switching device from off to on so that start timing of control is different for each electric motor.

An electric motor control device controls driving of electric motors connected in parallel with each other and includes a power converter converting power from a power supply, and supply the converted power to each of the electric motors, a switching device to be turned on to electrically connect the power converter and at least one of the electric motors and to be turned off to electrically disconnect the power converter and the at least one of the electric motors, a current detection unit detecting a current that flows in the electric motors, and a controller controlling the power converter on the basis of operation of the switching device, rotation frequency command values from an external device, and a value of the current detected by the current detection unit. The controller turns the switching device from off to on so that start timing of control is different for each electric motor.