BXX-2 phase sequence relay is mainly used for phase sequence detection or phase failure protection. When the phase sequence is correct, the relay operates to obtain output; When the phase sequence is incorrect or any phase of the AC circuit is disconnected, the relay will lock.
2. Structure and Working Principle
The relay adopts JK-11K, H, and Q type housing, and its external dimensions, rear terminals, and installation opening diagram are shown in Appendix 3. The back terminal is shown in Figure 1.

Figure 1 Rear terminal wiring
The relay consists of a small sealed relay, bridge rectifier, integrated block, transistor, voltage regulator, resistor, capacitor and other components.
3. Technical requirements
1. Rated value
The rated line voltage of the relay is 380V, and the rated frequency is 50Hz.
2. Voltage fluctuations
The allowable fluctuation range of relay voltage is 80% to 110% of the rated value.
3. Phase sequence judgment
When the phase sequence is correct, the relay operates. When the phase sequence is incorrect, the relay locks. When any phase in the three phases is disconnected, the relay locks and the LED lights up.
4. Power consumption
The total power consumption of the three phases shall not exceed 4VA.
5. The insulation resistance should not be less than 300M Ω.
6. Dielectric strength
Under standard test atmospheric conditions, the conductive circuits of the relay should be able to withstand a test voltage of 2kV (effective value) AC for 1 minute without insulation breakdown or flashover between the exposed non charged metal parts and the casing, as well as between the AC circuit and the contact circuit.
7. Contact performance
In the DC inductive (τ=5ms) circuit, U ≤ 250V, I ≤ 0.2A, 30W; in the AC (cos φ=0.4) circuit, U≤250V，I≤0.5A， It is 100VA.
8. The long-term allowable closing current of the contact is 1A.
The electrical lifespan of the relay is 5 × 103 times, and the mechanical lifespan is 104 times.
The weight of the relay is approximately 0.7kg.
4. Ordering Notice
Please specify the product model, name, rated line voltage, and installation method when placing an order.