The digital 3-phase current servo amplifier DS xx in combination with the brushless dc motor (synchro servo motor, CE motor) provide a drive solution free of maintenance and high control dynamics. The drive displays the well-known good control characteristics of dc drives without the disadvantages of the carbon brushes' wear and the commutation limits. The rotor moment of inertia is notably lower and the threshold power is greater than with equally constructed dc motors. This results in up to 5 times higher acceleration values. Compared to asynchronous motors with frequency converters the stability, the control range and the efficiency of the drive are considerably superior. The generated heat in the motor only occurs in the stator, therefore, the EC motors always have the protection rating IP 65. From the electrical view, the brushless dc motor is a synchro motor with a permanent magnet rotor and a three-phase current stator.
The physical characteristics correspond to those of dc motors, i.e., the current is proportional to the torque and the voltage is proportional to the speed. The speed control is stable up to the current limit (max. torque). In case of overloads the speed drops and the current remains constant. The speed/torque characteristic is rectangular. Current, speed, and position are precisely measured. The field frequency is not controllable, it is automatically adjusted. The motor voltages and the motor currents are sinusoidal. A maximum motor efficiency is achieved by means of a compensating current control. The DS 2420 drives can be used as single-axis position amplifier or torque or speed amplifier. The position and speed actual value is generated in the encoder unit (resolver or incremental encoder). The encoder pulses are emitted from the amplifier for a superordinate PLC/CNC control. The control circuits of current, speed, and position are PID controllers which are easy to program. They can be programmed by means of a PC or a programming box. The communication with superordinate controls is effected by means of BUS systems (standard CAN-BUS, RS232) or by analog interfaces.
Application in all kinds of battery-driven machines and installations with a drive power of 1kW, especially as 4Q-servo-drives for highly dynamic acceleration and braking cycles, for a wide control range, for a high efficiency, for small motor dimensions, for a uniform, accurate and smooth running, to be used for speed or torque control or combined speed/torque control incorporated within or independent of position control loops. Used for drives with constant speed as in conveyors, spindle drives, pumps, transversal or longitudinal pitch drives, synchronous multiple motor drives. Synchro-servo-drives are more compact than other electric drives.
They are used in assembly machines, testing machines, sheet-metal working machines, machine tools, plastic working machines, knitting and sewing machines, textile working machines, grinding machines, wood and stone working machines, metal working machines, food processing machinery, robots and handling systems, conveyors, extruders, calenders, and in many other machines and installations.