Abstract: A commutation cell is configured for limiting switching overvoltage. The commutation cell includes a power electronic switch having a parasitic emitter inductance through which a voltage is generated upon turning off of the power electronic switch. The commutation cell also includes a dynamically controlled compensation circuit connected to the parasitic emitter inductance. The compensation circuit applies a controllable portion of the voltage generated through the parasitic emitter inductance at turn-off of the power electronic switch to control the voltage generated through the parasitic emitter inductance. A power converter includes a pair of commutation cells and a compensation circuit of the commutation cell.

Abstract: An embodiment of a liquid cooled external rotor electric machine includes a stator, a generally cylindrical liquid cooling assembly secured to the stator therein, a rotor including a generally cylindrical shaped support having permanent magnets secured to its inner surface, an output shaft coaxially mounted to the rotor therein and a coupling assembly that biases the cooling assembly onto the stator and operatively mounts together the stator and cooling assembly to the output shaft. Mounting the shaft to the rotor and to the liquid cooling system yields a compact assembly where no housing is required for the alignment of the stator and rotor.

Abstract: The present disclosure relates to a commutation cell configured for limiting switching overvoltage. The commutation cell includes a power electronic switch having a parasitic emitter inductance through which a voltage is generated upon turning off of the power electronic switch. The commutation cell also includes a dynamically controlled compensation circuit connected to the parasitic emitter inductance. The compensation circuit applies a controllable portion of the voltage generated through the parasitic emitter inductance at turn-off of the power electronic switch to control the voltage generated through the parasitic emitter inductance. A power converter comprising a pair of commutation cells and a compensation circuit of the commutation cell are also disclosed.

Abstract: A turbine exhaust case for a gas turbine engine has an outer shroud and an inner shroud concentrically defining therebetween an annular gaspath for channelling hot gases. A plurality of circumferentially spaced-apart turbine exhaust struts extends radially across the hot gaspath. The inner shroud may be provided in the form of an acoustic panel. The acoustic panel has a radially outwardly facing surface defining the radially inner flow boundary surface of the gaspath. The acoustic panel is mechanically fastened to the radially inner end of the struts.

Abstract: A rotor disc, such as one made of a damage intolerant material or other material sensitive to stress concentrations, has at least one balancing assembly which includes a plurality of circumferentially spaced-apart sacrificial protrusions projecting between adjacent stress-relieving slots. Selective material removal is permitted from the rotor disc, while managing stress concentrations in the rotor disc created by such material removal, such that the rotor disc may be balanced without detrimentally affecting its service life.

Abstract: A turbine exhaust case for a gas turbine engine has an outer shroud and an inner shroud concentrically defining therebetween an annular gaspath for channelling hot gases. A plurality of circumferentially spaced-apart turbine exhaust struts extends radially across the hot gaspath. The inner shroud may be provided in the form of an acoustic panel. The acoustic panel has a radially outwardly facing surface defining the radially inner flow boundary surface of the gaspath. The acoustic panel is mechanically fastened to the radially inner end of the struts.

Abstract: A rotor disc, such as one made of a damage intolerant material or other material sensitive to stress concentrations, has at least one balancing assembly which includes a plurality of circumferentially spaced-apart sacrificial protrusions projecting between adjacent stress-relieving slots. Selective material removal is permitted from the rotor disc, while managing stress concentrations in the rotor disc created by such material removal, such that the rotor disc may be balanced without detrimentally affecting its service life.

Abstract: A rotor disc, such as one made of a damage intolerant material or other material sensitive to stress concentrations, has at least one balancing assembly which includes a plurality of circumferentially spaced-apart sacrificial protrusions projecting between adjacent stress-relieving slots. Selective material removal is permitted from the rotor disc, while managing stress concentrations in the rotor disc created by such material removal, such that the rotor disc may be balanced without detrimentally affecting its service life.

Abstract: The invention concerns a rotating electric motor system capable of vibrating and a method for operating a rotary electric motor capable of vibrating. The system comprises an electric motor having a rotor and a stator, the rotor and the stator forming a unit vibrating within an audio frequency range; a power amplifier powering the electric motor, the power amplifier having a passband including at least the audio frequency range; and a signal generator generating a signal controlling the power amplifier. The signal generator comprises at least the audio frequency range. The control signal has a continuous component for rotating the rotor with respect to the stator, and an alternating component for inducing mechanical vibration in the unit capable of vibrating.

Abstract: The invention concerns a rotating electric motor system capable of vibrating and a method for operating a rotary electric motor capable of vibrating. The system comprises an electric motor having a rotor and a stator, the rotor and the stator forming a unit vibrating within an audio frequency range; a power amplifier powering the electric motor, the power amplifier having a passband including at least the audio frequency range; and a signal generator generating a signal controlling the power amplifier. The signal generator comprises at least the audio frequency range. The control signal has a continuous component for rotating the rotor with respect to the stator, and an alternating component for inducing mechanical vibration in the unit capable of vibrating.

Abstract: The invention concerns a rotating electric motor system capable of vibrating and a method for operating a rotary electric motor capable of vibrating. The system comprises an electric motor having a rotor and the stator, the rotor and the stator forming a unit vibrating within an audio frequency range; a power amplifier powering the electric motor, the power amplifier having a passband including at least the audio frequency range; and a signal generator generating the signal controlling the power amplifier. The signal generator comprises at least the audio frequency range. The control signal has a continuous component for rotating the rotor with respect to the stator, and an alternating component for inducing mechanical vibration in the unit capable of vibrating.