Working principle of air damping type time relay

Air damping type time relay is to use the principle of air damping to obtain delay. It is mainly composed of electromagnetic system, air chamber and contact system.

When the coil power will attract 1 to 2 armature suction, the armature and the piston rod has a distance between 3. In spring 4 release under the action of the piston rod moves downwards in umbrella piston 5 is fixed on the surface of a layer of rubber film 6. Therefore, when the piston moves downward, resulting in a thin air space above the film, the piston under the pressure of the air, can not be rapidly decreased. When the air enters from the air inlet 7, the piston drops gradually. When moving to the final position, lever 8 causes the microswitch to act 9. The delay time is the time from the time when the electromagnet attracts the coil to the microswitch. The size of the air inlet is adjusted by adjusting the screw 10 to change the delay time. When the suction coil is cut off, the reset spring 11 is rapidly reset. The air is rapidly discharged from the vent 12. The time relay shown in the figure has two delay contacts: one is a normally closed contact when the power is turned off, and the other is a normally open contact. In addition, there are two instantaneous action of the contact, that is, after the switch micro switch instantaneous action 13. Relay manufacturers

The air time relay has a large delay range, 0.4 to 60 seconds and 0.4 ~ 180 seconds, the structure is simple, but the accuracy is poor.