CND 70 series are full-digital compact silicon controlled stator voltage regulators with the maximum output power of 580kW used for speed regulation and control of three-phase wound-rotor motor. The regulators are applicable to drive control systems with high requirements, and available for single-motor or multi-motor drive.

The other two parallel silicon controlled modules in the power part are used for torque switch and four-quadrant operation of devices, which can realize electronic commutation of the output phase through auto-commutation. The devices can run under the mode of plug braking or motor drive according to load conditions, do not require for traditional stator contactors, and are highly dynamic and stable in operation.

Voltage regulation of the motor stator is realized through control of conduction angle of the three pairs of antiparallel silicon-controlled rectifier (SCR). In the process of voltage regulation, the frequency of motor stator voltage is not changed, but remains the same with that of power supply.

SCR is controlled by the door unit that generates the trigger pulse in synchronization with line voltage. The electron plate is separated with line voltage through the trigger pulse transformer, the working condition of which is shown by the seven-segment display or advanced communicator.

Parameter settings of the devices (including controller parameters, limits etc.) are stored in a non-volatile memory. It is easy to change the address and parameter values by digital adjustment with the control panel or advanced communicator.

CND70 series stator voltage regulation combines the following two conventional modes of speed regulation.

— To change the voltage of motor stator through control of input voltage.

— To change the characteristic curve of motor through modifying the rotor resistance.

This combination has good effect of control, for not only their strong points are fully utilized, but also their respective weak points are avoided.

-Ideal solutions for modification of old system;

-Modification scheme to improve the performance of old control system;

-Low cost of modification, as the original motor, resistor, cable and cabinet can be used continuously;

-Rapid, flexible and user-friendly solutions with short downtime;

-Cost-saving solutions for new systems;

-Cost-saving solutions for new systems;

-Important control functions integrated in the device, simple for external control and inter-connection;

-Simple and easy for planning and configuration;

-Time and cost saving for installation and commissioning;

-Very stable in operation, avoiding serious wear of system components;

-Fully utilized the advantages of wound-rotor motor, high in control quality;

-Designed with stator voltage regulation and control, sound in dynamic control;

-Compatible with all standard elements and interfaces of crane;

-Special technologies not required.