Finder time relayIt is an automatic switching device with time-delay control function. So how should the finder time relay be reset?
The terminal blocks of our common finder time relay can be divided into power terminals and contact terminals. However, some finder time relays have a group of reset function terminals, which are rarely used, but this reset function is very practical, flexible and convenient in some applications.
This reset function is that after the power supply of the finder time relay is turned on, the finder time relay starts timing work. At this time, contact the 3 and 4 reset function pins (only the passive switch can be connected, and the power supply is prohibited), and the time delay contact of the finder time relay will return to the initial position, and the timing will be cleared. If the 3 and 4 reset function pins are disconnected, the finder time relay will be timed again.
So careful friends may find a problem, what? This power-off delay relay can only enter the timing mode after disconnecting the power supply. What is the significance of this reset? The reset function of the power-off delay relay is actually an auxiliary function and an extension, which can be used in the circuit according to the actual control requirements.
1. Generally, the finder time relay will reset automatically when it is powered off. The finder time relay that controls the cumulative timing when the power supply is cut off will not reset, and when the working power supply is cut off, it will reset automatically.
2. Most of the current finder time relays are electronic, and there are few old-fashioned leather cavity time-delay relays. There is a circuit board inside the electronic type, on which there is a time-based circuit and an output relay. By selecting the normally open contact and normally closed contact of the finder time relay, simple time-delay conduction or time-delay disconnection can be achieved. Without a reset terminal, power failure can be reset. When the power is turned on, the timer starts. When the set value is reached, the finder time relay acts and stays until the power is cut off.
3. Finder time relay can be divided into power on delay type and power off delay type. Power on delay relay refers to that when the relay coil is powered on, after a certain time delay, the relay is closed again, and when the power is cut off, the coil is released immediately; Power off delay relay means that after the relay coil is powered off, the relay coil will be released after a certain time delay.
When the coil is energized, the armature and the support plate are attracted by the iron core and move down instantaneously, so that the instantaneous action contact is connected or disconnected. However, the piston rod and lever cannot fall together with the armature at the same time, because the upper end of the piston rod is connected with the rubber film in the air chamber. When the piston rod starts to move downward under the action of the release spring, the rubber film will sag downward, and the air in the upper air chamber becomes thin, so that the piston rod is damped and slowly drops. After a certain time, when the piston rod drops to a certain position, the time-delay contact is pushed by the lever to open the dynamic breaking contact and close the dynamic closing contact. The delay time of the relay is from the time when the coil is energized to the time delay contact completes its action. Adjusting the size of the air inlet hole of the air chamber with screws can change the length of the delay time.
When the suction coil is powered off, the relay resets under the action of the recovery spring. The air is quickly discharged through the air outlet.