Working principle:

Time relay is a kind of control electric appliance which realizes delay control by using electromagnetic principle or mechanical principle. There are many kinds of them, such as air damping, electric and electronic.

Time relay can be divided into two types: power delay type and power delay type.

The air-damped time relay has a wide delay range (0.4 ~ 60s and 0.4 ~ 180s), which is simple in structure but low in accuracy.

When the coil is energized, the armature and supporting plate are attracted by the core and move down instantaneously, making the instantaneous action contact connected or disconnected. However, the piston rod and lever cannot fall along with the armature at the same time, because the upper end of the piston rod is attached to the rubber film in the air chamber. When the piston rod begins to move downward under the action of the release spring, the rubber film then depresses downward, and the air in the upper air chamber becomes thinner, which causes the piston rod to slow down under the action of damping. After a certain period of time, when the piston rod drops to a certain position, it pushes the delayed contact through the lever to make the dynamic breaking contact disconnect and the dynamic closing contact close. The period from the time the coil is energized to the time the delayed contact completes the action is the delay time of the relay. The length of the delay time can be changed by adjusting the size of the air chamber inlet with a screw.

When the suction coil is cut off, the relay is restored by the action of the recovery spring. Air is discharged rapidly through the vent.

Main Features:

1. Air-damped time relay is also known as airbag time relay, which conducts delay according to the resistance generated by air compression. Its structure is simple, the price is cheap, the delay range is large (0.4~180s), but the delay precision is low.

2. Electromagnetic time relay has a short delay time (0.3~1.6s), but its structure is relatively simple, and it is usually used in power failure delay occasions and direct current circuits.

3, the principle of the electric time relay is similar to a clock, it is driven by the internal motor reduction gear rotation to obtain the delay. This kind of relay has high delay precision and wide delay range (0.4~72h), but its structure is complicated and its price is very expensive.

4, transistor type time relay is also known as electronic time relay, it is the use of delay circuit to delay time. This kind of relay has high precision and small size.