Passing frequency signal through the neutral cable of 3-phase ac supply

[Olushola]

Please can anyone help me.Is it possible to pass frequency signal through the neutral cable of 3-phase ac supply and use it to switch on the relay?Or what signal one can pass through the 3-phase ac supply to switch on relay?Help is urgently needed.

[AJISH ALFRED]

Hi Olushola,

It is very much possible, I’ve tried it. I successfully transmitted and received audio frequency signals. In your case, you need a circuit which decides whether to turn on or off the relays based on the presence or absence of the signal.

My ciruit was a extremely simple but little bit dangerous, since there is no actual isolation of the power lines from the circuit.

You can find lot of examples of powerline signal couplers from the net. Here is the link to one such device which I’ve found which uses optical isolation from power lines.

 

http://datasheet.octopart.com/0557-7700-11-Bel-Fuse-datasheet-13509475.pdf

 

[Olushola]

Thank you.But any loss in frequency along the neutral cable?

[AJISH ALFRED]

Yes, there was a slight drop in the amplitude of the signals. In my case it happend mainly due to the coupling circuit and not because of the neutral wire. 

You can add a simple amplifier at the receiving end if the drop is too much.

[Olushola]

Thank you ‘am very greatful.Please which method is more reliable using  rf wireless  control and passing frequency signal through neutral cable to switch ON relay?

[AJISH ALFRED]

Hi Olusha,

I can’t suggest you any specific device, since I haven’t used any of them in my project. Do a research on them with the help of internet, go through their data sheets and find the most suitable one for your project.

[Olushola]

Thank you.

[AJISH ALFRED]

You are welcome. Expecting to hear more about your project work.

[Olushola]

Thank you. I will let you know about the out come of the project.

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