Uranit, Uran-isotopentrennungs-gesellschaft M.b.h.

Urenco Deutschland Gmbh

Johann Mundt

Horst Kasper

Eckhard Pritsch

In a method of operating and controlling hysteresis motors energized by a three-phase power supply and individually monitored by an operating monitoring system, whereby the effective power output of the individual motors is determined and the three-phase voltage is changed if the effective power output deviates from a predetermined range, the hysteresis motors are first energized at an intermediate range voltage until they reach nominal speed and are then running at synchronous speed, the supply voltage is then increased to an upper range, where the remanent magnet pole strength is impressed on the armature and then reduced to a lower range for continuous operation of the motors, the power output of the individual motors is monitored and, if it drops below a threshold indicating a switch to asynchronous operation, the operating voltage is again increased to the intermediate range for renewed synchronization.

Method for operating and controlling hysteresis motors

A method for optimizing the power input to a plurality of parallel connected hysteresis motors wherein a three phase alternating voltage source jointly supplies the motors with an adjustable operating voltage. The method includes measuring, during the operation of each motor, the phase angle difference between motor voltage and motor current and determining the power factor therefrom for each motor. The effective current value of each motor is measured during operation and is combined with the power factor to obtain the active current for each motor. An active current limit value at which each motor transitions from synchronous to asynchronous operation is measured once and stored for each motor prior to commencement of continuous synchronous operation. After the motors reach synchronous speed at rated voltage, the control voltage is adjusted to reduce the supply voltage to an optimum working point just above the voltage level at which a first one of the parallel connected motors begins to transition from synchronous to asynchronous operation. The active current of each motor is then compared with its associated limit value to determine whether it is operating synchronously or asynchronously. The control voltage of the voltage source is thereafter regulated for increasing the supply voltage to the rated voltage value when it is determined that one of the motors is operating asynchronously and for decreasing the supply voltage to the optimum working point when the motors are all determined to be operating synchronously.

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Jülich, Germany

Johann Mundt