The main function of finder intermediate relay is that when the number of contacts or contact capacity of other relays is insufficient, finder intermediate relay can be used to expand the number of contacts or increase the contact capacity, playing the role of intermediate conversion (transmission, amplification, overturning, shunting, memory, etc.). The rated current of the contact of finder intermediate relay is much greater than its coil current, so it can be used to amplify the signal. The combination of multiple finder intermediate relays can also form circuits with various logic operation and counting functions.
Structure and working principle of finder intermediate relay
The structure and working principle of finder intermediate relay are similar to that of contactor. It is mainly composed of electromagnetic mechanism and contact system, but there is no arc extinguishing device, and there are no main and auxiliary contacts. The main difference from the contactor is that it can respond sensitively to the changes of voltage and current. The number of contacts is large but the capacity is small. It is mainly used for switching small current circuits or as intermediate conversion of signals.
Finder intermediate relay is a widely used relay, which has the control functions of memory, transmission and conversion of information. It can also be used to directly control small capacity motors or other electrical appliances.
The structure of finder intermediate relay is basically the same as that of AC contactor, but its electromagnetic mechanism is small, compact and has a large number of contacts. Since the current passing through the contact is very small, the arc extinguishing cover is generally not equipped.
The circuit and current are very small, so the general finder intermediate relay does not need an arc extinguishing device. The finder intermediate relay coil shall be able to work reliably above the rated voltage of 850/0~105%.
Finder intermediate relay is applicable to the control circuit with AC voltage of 50Hz, voltage of 380V and DC voltage of 220V. It is used to control various electromagnetic coils to amplify signals or transmit signals to relevant control elements at the same time.
How to select finder intermediate relay?
1. The voltage or current of finder intermediate relay coil should meet the needs of the circuit;
2. The type and number of contacts of finder intermediate relay shall meet the requirements of control circuit;
3. The rated voltage and current of the finder intermediate relay contact should also meet the requirements of the control circuit;
4. Select AC or DC type relay according to circuit requirements.
What is the difference between finder intermediate relay and contactor?
1. The contactor is mainly used to connect and disconnect the high-power load circuit, and the finder intermediate relay is mainly used to switch the low-power load circuit;
2. Finder intermediate relay has multiple pairs of contacts, without the distinction of main contact and auxiliary contact, and each pair of contacts is allowed to pass the same current;
3. Finder intermediate relay is mainly used for signal transmission, and can also be used to realize multi-channel control and signal amplification;
4. Finder intermediate relay is usually used to expand the number and capacity of contacts of other electrical appliances.