（1） Railway signal requirements for relays

JWXC-7, JWXC-1700, JWXC-1000 non-polar relay signal relay is the main (or important) component in railway signal system. Its safety and reliability in operation are necessary conditions to ensure the normal use of various signal equipment. Therefore, railway signals have put forward strict requirements for relays, as follows:

(l) Actions must be reliable and accurate;

(2) Long service life;

(3) Having sufficient ability to close and disconnect circuits;

(4) Has stable electrical and time characteristics;

(5) It can maintain high electrical insulation strength even under significant temperature and humidity changes in the surrounding medium.

Specific requirements can be found in "Technical Standards for Signal Maintenance Rules" 11 Relay 11 1. General rules.

According to the reliability of the work, signal relays can be divided into three levels:

JWXC-7, JWXC-1700, JWXC-1000 non-polar relays have a working air gap at the blade of the yoke in addition to the working air gap between the armature and iron core in the electromagnetic system, in order to reduce the magnetic potential drop of the magnetic circuit and improve the sensitivity of the relay.

① Coil

The coil is horizontally installed on the iron core and divided into front and rear coils. The reason for using double coil is mainly to enhance the adaptability and flexibility of the control circuit. It can be controlled by single coil, double coil series or double coil parallel according to the circuit needs.

The coil is wound on a coil frame, which is pressed from phenolic resin. In order to increase the buffering time, a copper damping coil frame is used for the slow release type infinite relay. The coil is tightly wound with high-strength enameled wire, and the tap is welded with lead pieces. The connection between the coil and the power supply piece

②yoke iron

The choke iron is in the shape of an L continent, stamped and formed from an electrical pure iron plate, and coated with multiple layers of chromium protection on the surface.

③Armature

The armature is angular in shape and is fixed to the blade of the yoke by a butterfly shaped steel wire clamp, allowing for flexible movement. The armature is formed by stamping electrical pure iron,

There are heavy hammer pieces riveted on the armature to ensure that it returns by gravity. The heavy hammer plate is made of thin steel plate, and its number is determined by the number of contact groups, so that the weight of the armature basically meets the needs of the rear contact pressure. Generally, three pieces are used for 8 groups of rear contacts, two pieces for 6 groups, one piece for 4 groups, and not for 2 groups.

There is a stopper on the armature, which is made of brass and installed at the closure between the armature and the iron core. There are 6 thicknesses of stoppers, which vary depending on the specifications of the relay. They can be removed and replaced according to the specifications. The stopper is used to increase the magnetic resistance of the relay in the suction state, reduce the residual magnetic effect, and ensure the reliable lowering of the relay.