To control the operation of a laundry washing machine or dryer, according to the load, the charged drum (1) is rotated initially for the motor (4) torque to maintain a constant rotary speed. On acceleration, the motor (4) torque required is registered to spin the charged drum (1). The control electronics (5) gives the quotient of the difference value of the two torques and the angular acceleration of the drum (1), for a quotient which is proportional to the inertia of the drum (1), and increases proportionally to the laundry charge. A setting value for the control is derived from the quotients.

Laundry washing or drying machine control

In a commutatorless motor device including a synchronous motor driven through a frequency converter including gate-controlled electric valves, and a device for detecting the phase voltages of the synchronous motor, a device for dividing the detected phase voltages by a signal corresponding to the speed of the synchronous motor. The outputs of the dividing device are fed to a logic signal converter which converts them into signals corresponding to the position of the rotating magnetic field of the synchronous motor. The outputs of the logic signal converter are passed through a logic circuit and a gate-pulse generating circuit for generating gate pulses for controlling the electric valves of the frequency converter.

Commutatorless motor device

The application of the modified variable frequency controller is principally to machines operating in all four quadrants. In order to ensure that there is always adequate commutation on the inverter section a reduction in output from one torque/speed point to another is effected by two controls. The load current set point is not reduced below a predetermined critical value necessary to ensure safe commutation. Any necessary further reduction is achieved by altering the magnetising current set point. A controller for this purpose can be added to the conventional variable frequency equipment.

Variable speed async. machine supplied via inverter - operates with separate control set points for magnetising and load currents

Einrichtung zum steuern bzw. regeln des drehmoments eines wechselstrommotors

Steuersystem und speiseverfahren fuer einen wechselstrommotor

The static converter, for an asynchronous machine, shifts the rotor frequency at large field reductions and small torque requirements such that a minimum current is maintained. The power regulating quantity is derived either from the converted voltages and currents or from the voltage and current in the converter's intermediate circuit.

Static converter for async. machine - shifts rotor frequency to minimise current consumption at low torque requirement

Torque and speed of the asynchronous rectifier machines are controlled, and the machines are supplied from the mains through a rectifier unit consisting of a pulse current rectifier and phase sequence rectifier with impressed intermediate circuit current. Input voltage (Uc) of the pulse current rectifier can be controlled within a freely selectable sinusoidal tolerance band using a filter (Li, C) on the main side. The single phase network has a transformer (T) on the main's side and has the pulse current rectifier (PSR) connected with a phase following rectifier (PFSR) on the secondary side. A number of measured value converters (MUuO) are connected to tappings at various stages in the circuit.

Guenter Dipl Ing Goelz

Papers

Static converter for async. machine - shifts rotor frequency to minimise current consumption at low torque requirement

Multiple asynchronous rectifier machines - are operated by LC filter on mains side controlling pulse current rectifier input voltage