Working principle of power-off time delay relay

The working principle of power-off time delay relay is that when the coil of time relay is powered on, each delay contact will act instantly, while after the coil is powered off, the contact will be in the delay setting state, and when the set delay arrives, the delay contact will return to the initial state.

Because of its working state (no external power supply is needed in the delay process) and the contact of the control contact during the delay process (normally open contact should be kept on when it becomes on; Normally closed contacts become open and should be kept open) to meet its control requirements.

The power-off time delay relay consists of the earliest separated devices (low delay accuracy and short delay time); Using the corresponding programmable timing integrated circuit or cmos counting frequency division integration to complete the delay, compared with it, it has the characteristics of high delay accuracy and long delay time. This can meet the control situation of long delay in power failure.

Extended data

Precautions:

1, the relay power supply voltage should work within the allowable voltage fluctuation range, usually 85% ~110% of the rated value; The peak ripple coefficient of DC voltage is less than 5%. If the relay power supply has a strong inductive load and works frequently, it should be considered to add and use surge absorbing devices at the relay power supply terminal to withstand a higher surge voltage (1500v) and prevent the relay power supply from being broken down and burned. ?

2. When the relay is in use, the power-on time must be greater than 1s, so that the secondary power supply inside the relay has enough energy reserves to ensure that the load is connected or disconnected according to the preset time after the power supply is disconnected; If it is necessary to use the external reset signal function of the relay, the turn-on duration should be not less than 50 milliseconds to ensure the normal operation of its reset function. It is forbidden to connect power supply, active signal or grounding at the reset signal terminal, otherwise the relay will be damaged.

3. A 2-winding self-locking relay is used inside the power-off time delay relay. Compared with ordinary relays, relays have poor adaptability to the environment, especially in places with strong magnetic fields and large impact vibration, and should be avoided as much as possible when used.