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- Should I run a relay continuously? 1 answer
I would try to make it as clear as possible. I have a relay, and it has five pins( NC, NO, C, and coil) like any basic relay.
Now, I want to apply a logic - when the input (I would say it BMS from now) is 230V ( the mains supply is on) the alarm system should not buzz ( the alarm work at 230V mains supply) and when the input(BMS) is cut off (0V) the alarm system should start buzzing. In short, the alarm should start when the input is 0V and should turn off when the input is 230V mains. I realized the best way I can achieve is by using a relay and 2 different mains supply. The BMS will control the coil of the relay. The second power supply mains will be connected to the NC pin of the relay. And the alarm (hooter) will be connected to the C or common pin of the relay. Now, we consider two cases.
Case 1: The second power supply is On and BMS is also on.
When this is the case, the Coil of relay is high as we have connected BMS to the relay coil. So, NO and C of the relay will be connected to each other. We have nothing connected in the NO pin so the C pin would be low and the alarm will not start. Exactly what we want.
Case 2: The second power supply is On and BMS is cut-off
In this case, the coil of the relay will be cutoff so NC and C of the relay will be connected to each other. The second power supply is connected to the NC pin and as it is shorted to C of the relay, it will start the alarm as it will receive the supply voltage from the second power supply. So, when the BMS is cut-off, the alarm starts. Still, exactly the case we want.
The problem is that the BMS will always be on usually and the relay will always be in the switched state( NO and C of the relay will be connected). It will be only when the BMS is cut-off the relay will come to normal state( NC and C of the relay are connected).
Now, coming to my question. As the relay will be in the switched state forever ( NO AND C is always connected), will it damage my relay? Will the self-life of the relay decrease in that case? I hope you got my question. If it will damage my relay, please read further. If not, I would not look for alternatives.
Please help if you have any alternative for achieving the same thing.
If there is any other way of the same functioning ( the alarm should start when the BMS is cut-off) without using relay or using relay but with different connections, please do let me know. I am open for suggestions and please do help. Thanks for reading as I know I wrote a whole story here. Thank you.