A device is provided for monitoring the compaction of concrete introduced into a slipform of a slipform paver by means of at least one concrete compacting device that has an asynchronous motor for driving an unbalanced mass which generates vibrations. The monitoring device comprises an apparatus for monitoring the stator current of the asynchronous motor, the apparatus being configured such that a change in the compaction of the concrete is determined based on an analysis of the stator current. The apparatus for monitoring the stator current of the asynchronous motor is preferably configured such that the amplitude spectrum of the stator current is determined in order to analyse the stator current. It is advantageous that the compaction of the concrete is not monitored using sensors which are exposed to harsh ambient conditions during operation of the slipform paver.

A device is provided for monitoring the compaction of concrete introduced into a slipform of a slipform paver by means of at least one concrete compacting device that has an asynchronous motor for driving an unbalanced mass which generates vibrations. The monitoring device comprises an apparatus for monitoring the stator current of the asynchronous motor, the apparatus being configured such that a change in the compaction of the concrete is determined based on an analysis of the stator current. The apparatus for monitoring the stator current of the asynchronous motor is preferably configured such that the amplitude spectrum of the stator current is determined in order to analyse the stator current. It is advantageous that the compaction of the concrete is not monitored using sensors which are exposed to harsh ambient conditions during operation of the slipform paver.

A superconducting rotating machine, including: a stator that has a tubular stator iron core and stator windings wound around the stator iron core and generates a rotating magnetic field; a superconducting rotor having: a superconducting squirrel-cage winding that is held rotatably with the rotating magnetic field of the stator on an inner peripheral side and has one or more rotor bars and end rings each made of a superconducting material; and a rotor iron core that has a plurality of slots to accommodate the rotor bars; a pulse voltage output unit that outputs a pulse voltage to shift the superconducting squirrel-cage winding to a magnetic flux flow state; a drive voltage output unit that applies a drive voltage to the stator windings to rotationally drive the superconducting rotor, wherein the pulse voltage output from the pulse voltage output unit is superimposed on the drive voltage.

A superconducting rotating machine, including: a stator that has a tubular stator iron core and stator windings wound around the stator iron core and generates a rotating magnetic field; a superconducting rotor having: a superconducting squirrel-cage winding that is held rotatably with the rotating magnetic field of the stator on an inner peripheral side and has one or more rotor bars and end rings each made of a superconducting material; and a rotor iron core that has a plurality of slots to accommodate the rotor bars; a pulse voltage output unit that outputs a pulse voltage to shift the superconducting squirrel-cage winding to a magnetic flux flow state; a drive voltage output unit that applies a drive voltage to the stator windings to rotationally drive the superconducting rotor, wherein the pulse voltage output from the pulse voltage output unit is superimposed on the drive voltage.

Monitoring conditions of an electric motor using stator current and voltage signals from power supplied to the motor is disclosed herein. The stator voltage and current signals may be used to calculate instantaneous power values which may be used to calculate slip. The slip may be used to monitor for a locked rotor condition during startup of the motor. The slip value may be used to provide thermal protection to the electric motor.

Monitoring conditions of an electric motor using stator current and voltage signals from power supplied to the motor is disclosed herein. The stator voltage and current signals may be used to calculate instantaneous power values which may be used to calculate slip. The slip may be used to monitor for a locked rotor condition during startup of the motor. The slip value may be used to provide thermal protection to the electric motor.

Electric motor, in particular induction motor, comprising a stator, a rotor and a control device which is arranged at the rotor. The three rotor windings are connected to a Rotor Control device with inverter and controller unit mounted on the rotor. A capacitor is placed in the DC link. The capacitor is supplied from the EMF induced in the rotor. The current in the rotor windings is advanced in order to achieve a 90 degree phase shift between rotor current and stator MMF vector. To achieve this the frequency and amplitude of the rotor current as well as the phase shift can be varied. Wherein the frequency of the rotor inverter is matching the slip frequency.

Electric motor, in particular induction motor, comprising a stator, a rotor and a control device which is arranged at the rotor. The three rotor windings are connected to a Rotor Control device with inverter and controller unit mounted on the rotor. A capacitor is placed in the DC link. The capacitor is supplied from the EMF induced in the rotor. The current in the rotor windings is advanced in order to achieve a 90 degree phase shift between rotor current and stator MMF vector. To achieve this the frequency and amplitude of the rotor current as well as the phase shift can be varied. Wherein the frequency of the rotor inverter is matching the slip frequency.

A method of a control system controls an inductance motor in a device that may include an impeller using a pressure compensation control system. The control system may be implemented in a respiratory pressure therapy device. The control system may include a sensor configured to provide a pressure signal indicative of the pressure of a flow of fluid produced by the device. A measured pressure may be compared to a set pressure to determine a pressure error. A slip frequency may be adjusted as a function of the pressure error in an attempt to eliminate or minimise the pressure error.

A method of a control system controls an inductance motor in a device that may include an impeller using a pressure compensation control system. The control system may be implemented in a respiratory pressure therapy device. The control system may include a sensor configured to provide a pressure signal indicative of the pressure of a flow of fluid produced by the device. A measured pressure may be compared to a set pressure to determine a pressure error. A slip frequency may be adjusted as a function of the pressure error in an attempt to eliminate or minimise the pressure error.