In contemporary production and construction, relays are widely used in industrial control. Among many relays, one kind of relay has a very special application principle. Today, finder time relay has entered many manufacturers. Time relay is a time-delay control relay, which does not make the contact act immediately after receiving the action signal, but delays the contact for a period of time. At present, finder time relay is widely used in various automatic control systems and motor starting control circuits.

Finder time relayIt is divided into two types: power on delay type and power off delay type. In terms of working principle, for power on delay type time relay, when the coil is powered on, the power on delay type contact acts after a period of time delay (normally closed contact is open, normally open contact is closed). When the coil is powered off, the contact immediately returns to normal state; For the power-off delay type time relay, when the coil is powered on, the power-off delay type contact will act immediately (the normally closed contact is disconnected, and the normally open contact is closed). After the coil is powered off, after a period of delay, the contact will return to the normal state.

There are many kinds of finder time relays, including air damping, electromagnetic, electric and electronic.

Air damping time relay, also known as air bag time relay, delays according to the resistance caused by air compression. It has simple structure, low price, large delay range (0.4~180s), but low delay accuracy.

Electromagnetic time relay has a short delay time (0.3~1.6s), but its structure is relatively simple. It is usually used in power-off delay occasions and DC circuits.

The principle of electric time relay is similar to that of clock. It is delayed by the rotation of reduction gear driven by internal motor. This relay has high delay accuracy and wide delay range (0.4~72h), but its structure is complex and expensive.

Electronic time relay, also known as electronic time relay, uses time delay circuit to delay. This relay has high precision and small size.

Today, when selecting time relays, we can generally follow the following rules:

According to the needs of the controlled circuit, decide whether the time relay is of power on delay type or power off delay type.

According to the voltage of the controlled circuit, select the voltage of the attracting winding of the time relay.

If the time delay requirement is high, transistor time relay or electric time relay can be selected. If the time delay requirement is not high, air damping time relay can be selected.