D P L
DD-1 grounding relay
product description:
DD-1 type grounding relay (hereinafter referred to as relay) is a transient overcurrent relay, used as grounding zero order overcurrent protection for high voltage three-phase alternator and motor for small grounding current power system.
The relay coil is connected to a zero-order current transformer (cable type, bus type) or to a zero-order current protection consisting of three phase current transformers.
When the zero point of the protected motor is grounded by impedance, the relay is connected to the differential circuit of the converter.
When the relay is connected to a zero-order current filter composed of three phase current transformers, the locking relay should also be connected to prevent misoperation caused by unstable current due to external crossing short circuit.
Product features:
Structure and principle
Relay is the instantaneous action composed according to the principle of electromagnetic, electromagnetic system has two coils, when the coil through the current pair in the magnetic moment magnetic flux.
Because the relay is used as the grounding protection in the small grounding current system, it requires high sensitivity, in addition to the gossamer with small reaction torque, the compensation winding is added in both coils, which form a closed loop through the capacitor (C=0.47 f) to compensate the retance of the magnetized coil, reduce the power required for the same magnetic flux in the conductive magnet, improve the sensitivity of the relay and reduce the loss.
The outgoing line of the relay coil is connected to the terminal of the relay base, and the coupling piece is installed so that the coil can be changed from series to parallel, so that the setting value of the relay is doubled.
The adjustment of the setting current of the relay is sufficient by turning the pointer on the dial to change the reaction torque of the gossamer, and the relay has a dynamic closing contact.
The internal wiring of the relay is as shown below.
The relay must be mounted vertically on the panel for front or rear wiring.
