Federal Research Institute of Semiconductor Devices Control and protective relay of three-phase electric installations Библиотека

Control and protective relay of three-phase electric installations

Control and protective relay of three-phase electric installations Control and protective relay (CPR) is intended for the production of alternating current in feed circuits of three-phase electric installations (electric motors, transformers and other equipment) with the purpose of increasing their reliability and service life.

The relay controls operating currents of an electric installation and switches it off in emergency conditions which are as follows:

• overloading in current of intolerable duration;

• underloading (idling);

• any-phases open fault;

• phase distortion in current.

The relay registers and stores the controlled current values and condition settings at the moment of emergency switching-off. It also stores information on the number and causes of emergency switching-off for an unlimited period of time.
The device is produced in five variants: CPR-25, CPR-50, CPR-250,CPR-500 and CPR-900.

Specifications

Limits of controlled currents in each of the three phases of electric installations as well as control of condition settings in overload, underload (idling) and disbalance currents are as follows:

CPR-25	CPR-50	CPR-250	CPR-500	CPR-900
2÷25 А	5÷50 А	20÷250 А	40÷500 А	90÷900 А

The delay time of protective switching-off at starting is varied from 3 to 250 s.
The delay time of protective switching-off at an phase open fault is 3+0.2 s.
Maximum number of registered emergency switching-off is no less than 255.
An electric installation can be switched off automatically in a preset period of time which is varied from 1 to 255 min.

Control and protective relay of three-phase electric installations The relay commutates an electric circuit of alternating current from 0.03 to 1.5 A at a voltage up to 380 V and is designed for control with magnetic starters and contactors from 0 to VI.
The relay is supplied from one phase of the alternating current circuit with a neutral wire, a voltage of 220 V and a frequency of 50 Hz.
The power supplied does not exceed 10 W.
The relay dimensions are no more than 70x85x54 mm (without a current detector).
The relay weight does not exceed 150 g.
A mobile indication panel ensures remote read-out from the relay and data representation on the screen of a digital display equipped with a liquid-crystal indicator with a resolution of 2 lines by 16 digits. It is also used to program a relay, introduce setting values on overloading, underloading (idling), current imbalance, as well as to set a delay time for switching off and re-starting of an electric installation. One panel can work with any number of relays.