circuit protects against ac-line disturbances

[joelalfuerto]

here is my power supply circuit...

 

[DXNewcastle]

Thanks Joel
I was hoping you'd show us the full circuit, starting right from the wall socket, including the wire that failed, and the transformer connections. I suspect that's where the problem lies, its certainly where the circuit failed, so it will surely help us to help you if you showed us the part that failed!

I wanted to check that there isn't any short between live and earth (or between neutral and earth), and there is no connection between the metal chassis and live nor between the 0volt reference of your circuit and live. I would also want to check that the transformer is appropriate for the application. I can't help if I don't know!!!
And I still don't even know if you have a fuse in the live line anywhere!

But looking at the drawing you've sent, I can see one terrible error straight away: the earth connection!In post #12 I said there must NOT be any connection to earth, because the circuit is already connected to the live and neutral wires from the mains.
The only earth connection must only be made to the chassis and NOT to any part of the circuit.
The common, 0volt, reference point throughout the circuit must be connected to the mains Neutral (and NOT to the Live).
The Neutral also goes to one end of the power supply transformer primary and to the neutral connection of the changeover relay contacts.
The live connection goes to : a) the other end of the power supply transformer primary, b) to the mains monitoring terminal of your circuit, and c) to the live connection of the relay contacts.

As I suggested, you should use a multimeter when the whole system is disconnected from the wall and check the resistances between the live pin and earth and the neutral pin and earth. There should be nothing less than a few Megohms.

I have to be quite clear with you Joel, working with live mains circuits puts you in danger and the hazard can, in extreme circumstances be fatal. If you are not absolutely confident that the connections you are making to the mains supply are safe then you really shouldn't be doing this.

 

[joelalfuerto]

hi guys any one who can help bout this! same with the one that i posted before its a circuit protection able to detect high voltage and low voltage and tripping it....

 

[DXNewcastle]

Image isn't showing. What's the precise problem?

 

[joelalfuerto]

can anybody help me about this problem.... i have a fire alarm circuit for detecting heat or change in temperature... but is it possible that it can have other application aside from fire detection.. as we all know LM35 can detect heat at the immediate vicinity..
so im looking for other application that needs to know if it is changing in temperature..

---------- Post added at 23:30 ---------- Previous post was at 23:27 ----------

can anybody help me about this problem.... i have a fire alarm circuit for detecting heat or change in temperature... but is it possible that it can have other application aside from fire detection.. as we all know LM35 can detect heat at the immediate vicinity..
so im looking for other application that needs to know if it is changing in temperature..

something that is needed to be protected against heat change..

 

[joomunm]

Hi Joelalfuerto,

I intend to build this circuit but I could not read the schematic diagram properly. Do you have a complete list of all the parts with the corresponding voltage rating?

Do you have a clear Schematic diagram or where can I download one properly?

Thanking you in anticipation.

Regards,

 

[joomunm]

Hi,

According to the schematic diagram, the relay coils works on 220V AC (Live and Neutral) and not on 9V DC. Moreover, the DC supply for the whole circuit is 5V DC and not 9V DC. However, IC1, Harris HV-2405E, supplies 5V DC only. Hope this helps.

By the way, I am looking for the list of all the parts used in this circuit. The schematic diagram is a bit blurred and difficult to read the resistance values. Can anyone help please? Thank in advance.