An alternator includes an exciter field device generating an exciter magnetic field in a first air gap, an exciter armature device configured to rotate with respect to the exciter magnetic field and impart a first voltage in a first set of coils at the first air gap, a main stator device including a second set of coils, and a rotor field device configured to be energized by the first current in the first set of coils and generate a main magnetic field that imparts a second voltage on the main stator device at a second air gap. The main stator device and the exciter field device lie in on a common plane normal to an axis of rotation, and the exciter armature device is inwardly spaced from the exciter field device, main stator device, and the rotor field device.

Certain embodiments of the present application relate to a variable frequency drive (VFD) cabin for a pump configuration including a mobile trailer on which the VFD cabin is to be mounted. The VFD cabin generally includes a medium-voltage VFD and a ventilation system. In certain embodiments, the ventilation system is configured to generate an overpressure condition within the cabin to discourage the entry of dust and debris into the cabin. In certain embodiments, one or more components of the medium-voltage VFD are coupled to the floor of the cabin via a vibration damping system. In certain embodiments, the VFD cabin may be directly coupled to a chassis of the mobile trailer without an intervening suspension being provided between the VFD cabin and the chassis.

The present disclosure provides a driving circuit of a fan motor to shorten a start time. The driving circuit drives the fan motor with a sensor. A control logic circuit controls an inverter circuit connected to the fan motor according to a Hall signal that indicates a position of a rotor of the fan motor. When the driving circuit is given an instruction to start a rotation, if the fan motor rotates at a speed lower than a predetermined rotational speed, the drive circuit starts the fan motor by sequentially switching between a second state in which the rotor is fixed at an initial position, a third state in which the fan motor is forcibly and synchronously started, and a fourth state in which the fan motor is Hall-driven.

The present disclosure provides a driving circuit of a fan motor to shorten a start time. The driving circuit drives the fan motor with a sensor. A control logic circuit controls an inverter circuit connected to the fan motor according to a Hall signal that indicates a position of a rotor of the fan motor. When the driving circuit is given an instruction to start a rotation, if the fan motor rotates at a speed lower than a predetermined rotational speed, the drive circuit starts the fan motor by sequentially switching between a second state in which the rotor is fixed at an initial position, a third state in which the fan motor is forcibly and synchronously started, and a fourth state in which the fan motor is Hall-driven.

An arrangement for a vehicle includes a fuel cell, an electric traction and/or propulsion motor, and a single cooling circuit cooling the fuel cell and the electric motor. The cooling circuit includes two parts: a first, high-flowrate and high-temperature part including a high-temperature exchanger and a second, low-flowrate and low-temperature part including a low-temperature exchanger. The first part cools the fuel cell and the second part cools the electric motor. The first part includes a high-flowrate pump, in particular for a high flowrate of between 8000 l/h and 9000 l/h and the second part includes a low-flowrate pump, in particular for a low flowrate of between 2000 l/h and 3000 l/h.

Certain embodiments of the present application relate to a variable frequency drive (VFD) cabin for a pump configuration including a mobile trailer on which the VFD cabin is to be mounted. The VFD cabin generally includes a medium-voltage VFD and a ventilation system. In certain embodiments, the ventilation system is configured to generate an overpressure condition within the cabin to discourage the entry of dust and debris into the cabin. In certain embodiments, one or more components of the medium-voltage VFD are coupled to the floor of the cabin via a vibration damping system. In certain embodiments, the VFD cabin may be directly coupled to a chassis of the mobile trailer without an intervening suspension being provided between the VFD cabin and the chassis.

An inductor for a converter of an electric machine includes a core defining a channel configured to receive transmission fluid on an outer surface of the core. Coils made of windings are wrapped on the core. The windings enclose an open side of the channel to define an oil flow passage, wherein oil flowing through the oil flow passage is in direct contact with both the windings and the core to absorb heat from the windings and the core.

A stator of an electric motor has a cylinder-shaped stator core. First core teeth and second core teeth are alternately arranged in the circumferential direction on the inner peripheral surface of the stator core. The second core teeth each have a cross-sectional shape perpendicular to the central axis of the stator core different from the cross-sectional shape of the first core tooth. A coil is assembled to the first tooth. The coil is assembled to one of the first core tooth and the second core tooth. The width of the second core tooth is reduced with a step of a curved surface at a boundary between the tip end portion and a portion behind of the tip end portion.

A stator of an electric motor has a cylinder-shaped stator core. First core teeth and second core teeth are alternately arranged in the circumferential direction on the inner peripheral surface of the stator core. The second core teeth each have a cross-sectional shape perpendicular to the central axis of the stator core different from the cross-sectional shape of the first core tooth. A coil is assembled to the first tooth. The coil is assembled to one of the first core tooth and the second core tooth. The width of the second core tooth is reduced with a step of a curved surface at a boundary between the tip end portion and a portion behind of the tip end portion.

An article can include a ceramic insulator with an interior surface defining a recess, an insulator aperture in the interior surface, and an insulator cooling channel extending through at least a portion of the ceramic insulator to the insulator aperture. A first conductor can be at least partially disposed within the recess.