hello people
I need your help once again, so I have got this battery tripping unit it is supplied by two sources, one is 220VAC supply and the other one 30VDC from the batteries. what happens is that when the AC supply cuts off due to power failure or something the DC supply from the batteries kicks in. so now what I need is a circuit that will monitor the AC supply, if it drops below 100VAC or lost completely there should be an alarm which will serve as an indication that the power is lost. I hope I have explained clearer.

thank you in advance

 

I do understand that:
You want a signal change when a voltage drops below 100VAC and a second signal when it disappears.
Buy a transformer 220V input output below the 12V.
Rectify and use the dc to feed a relay (normal open) is closed now.
If you want a 1/2 voltage detection use a zener N and a PFet to drive the relay.

I you want a RR you should use a Pic12F series with serial data communication and ADC.
This allow you to send status/ switch and monitor the AC and 30V also when needed.
I prefer the last as a real PIC lover.

Let me know if you want the schematic.

Picbuster

 

I wonder if a simple window comparator circuit would be sufficient here?

 

I do understand that:
You want a signal change when a voltage drops below 100VAC and a second signal when it disappears.
Buy a transformer 220V input output below the 12V.
Rectify and use the dc to feed a relay (normal open) is closed now.
If you want a 1/2 voltage detection use a zener N and a PFet to drive the relay.

I you want a RR you should use a Pic12F series with serial data communication and ADC.
This allow you to send status/ switch and monitor the AC and 30V also when needed.
I prefer the last as a real PIC lover.

Let me know if you want the schematic.

Picbuster

thank you very much but I would certainly like to see a schematic diagram if you don't mind. just send it please

 

Included the two files.
You have to rename the .txt in .c.

Good luck.

Picbuster

 

Included the two files.
You have to rename the .txt in .c.

Good luck.

Picbuster

thanks man

 

Just use 2 relays and 2 zener diodes connected to a bridge with an electro.

 

I hope everyone is sitting down for this: Colin has the right idea.

The stated requirement is for one alarm only, one that sounds when AC power is lost. This can be done with one SPDT relay with a 110 Vac coil, with the normally-closed contacts switching a battery-powered alarm of your choice. Note that the detection threshold will be very coarse; the relay might not drop out until the input AC is below 60-70 V. If you need more accurate detection, then circuits happen.

ak

 

Just use 2 relays and 2 zener diodes connected to a bridge with an electro.

thank you man let me try it out,just that I am new to this so I am still learning

 

Just use 2 relays and 2 zener diodes connected to a bridge with an electro.

thank you man

I hope everyone is sitting down for this: Colin has the right idea.

The stated requirement is for one alarm only, one that sounds when AC power is lost. This can be done with one SPDT relay with a 110 Vac coil, with the normally-closed contacts switching a battery-powered alarm of your choice. Note that the detection threshold will be very coarse; the relay might not drop out until the input AC is below 60-70 V. If you need more accurate detection, then circuits happen.

ak

ayt man thanks lets see if it happens\

 

thank you man

ayt man thanks lets see if it happens\

can you give me a clue if possible maybe a circuit diagram

 

can you give me a clue if possible maybe a circuit diagram

You do realize that you just quoted and responded to your own post, right?

 

I hope everyone is sitting down for this: Colin has the right idea.

The stated requirement is for one alarm only, one that sounds when AC power is lost. This can be done with one SPDT relay with a 110 Vac coil, with the normally-closed contacts switching a battery-powered alarm of your choice. Note that the detection threshold will be very coarse; the relay might not drop out until the input AC is below 60-70 V. If you need more accurate detection, then circuits happen.

ak

can you send me just a simple circuit man for this