trigger relay current draw

[jim63]

Hi all, I set up my alarm system some years ago which has multiple sounders, So obviously I have an additional power supply as the panel could not cope with the total current draw, It all works fine btw, my only question is where the current is being drawn from for the trigger relays, is it coming from the panel or the psu?' the positive supply input for the bell and strobe relays come from psu,and the negative supply input for the relays comes from the bell and strobe from the panel respectively.
The panel and psu are referenced together, so their negatives are linked.
Basically all I want to know is where the current for the trigger relays is being drawn from?
hope this makes sense, I replaced battery a few days ago on both panel and psu, I was having a look at the setup and just curious.
thanks

 

[jim63]

Its just 2 relays btw, one for the bell and the other for the strobe.

 

[sparkymarka]

Both

 

[jim63]

Thanks, was just curious to know, as I will be adding more devices to the panel, The relays used to be supplied from the panel but the issue with that is not all sounders would activate in the event the panel lost power or destroyed, as they still have a supply from the psu. Sorry to sound daft but if the relays draw power from both panel and psu, is the current from them halved between the panel and psu? IIRC each relay draws about 60ma.
thanks

 

[sparkymarka]

No ....what ever the current draw is for the relay from the panel ...plus what ever it supplies from the psu !

 

[jim63]

No ....what ever the current draw is for the relay from the panel ...plus what ever it supplies from the psu !

Thanks, so whatever the relay draws, lets say each relay draws 60ma,both would draw 120ma from the panel and the psu? Is that correct thanks, sorry to sound like a noob.
thanks

 

[sparkymarka]

No ....you may be taking 1amp from the psu depending on what you a powering from the relay ?!

 

[jim63]

No ....you may be taking 1amp from the psu depending on what you a powering from the relay ?!

****,so i could be damaging the panel the way its currently setup? the relays in question supply 3 sounders around the house, the total current for them is just over 1amp!.

 

[jim63]

Do you suggest I supply the relays from the panel only like it was before?, am I risk damaging the panel with the way its currently set up? I' a bit worried now.

 

[jim63]

What have I done wrong? What is currently happening being the panel and psu when the system is going into alarm? The additional sounders are supplied from the psu and the relays contacts, the relay coil input to trigger them is supplied from the psu positive and the bell and strobe negatives from the panel.
thanks

 

[sparkymarka]

Go and have a drink ....it’s newyears eve ...nobody said it was wrong and unfortunately my crystal ball is broken ...

 

[jim63]

I certainly will, but just put my mind at rest, Am I causing damage to the panel? See my post above on how its wired up, If you answer this for me I promise I will be out your hair. thanks
The panel is rated at 1 amp and the psu is 2 amp.

 

[sparkymarka]

No worse case it would blow the fuse

 

[jim63]

No worse case it would blow the fuse

Okay, hopefully that is worst case, I just want to be assured that the psu total load is not being transferred over to the panel due to the way the relay coil inputs are connected?,if that is what is happening could that be fixed by removing the psu positive from the relay input, and replace with the panel 12v so only the panel supplies the relays?, The total current on the psu is 1.2 amps in alarm, and the panel current in alarm is around 860ma ish, I sure hope the power supply is not adding 1.2amps to the panel because if it is then that is entirely defeating the purpose of the psu in the first place, It may as well not exist if that is what is going on!
This is so confusing?

 

[scott1980]

It's difficult to say what is going on from what you describe. You would normally only need to use relays if you're going over the switching current capacity of the panel output (most bell/strobe outputs will have a maximum rating, usually around 500ma)

Using relays, I would be connecting the 12v supply to the relay to the panel 12v supply, then the 0v supply to the relay to which ever output you want to trigger that particular relay (bell output for instance)

Then, you would use the aux power supply to feed whatever you want (additional sounders etc), switching the negatives of these sounders via the N/O of the relay contact. Connect the relay common contact to the 0v on the aux power supply and you have totally isolated it from the control panel, so that the panel is powering the relays and the power supply is powering the sounders.