fire alarm switching 110 vac controlled by 12 vdc

Thread Starter

smokey4111

Joined Jan 29, 2019
8
gamewell fire alarm 1961 using teletype, low voltage want to control 110 vac lights and horn.
The relay on the alarm is controlled when lever is pulled down running and mechanical timer with tooth wheel that turn on and off relay. The relay opens the circuit low voltage is dropped then turned on to give alarm location.
I want to add 110 vac light and horn using a relay to control 110 vac. with 12 vdc for the low voltage.
The problem is when the timing wheel stops the contacts are closed on the alarm.
Need a relay that will power up the 110 vac as the points on the alarm closes and disconnect when the points open, then disconnect when the alarm timer stops ( the points close at the time)
Help finding the right controller or relay and wiring diagram (may need time)
 

Yaakov

Joined Jan 27, 2019
1,612
Welcome to AAC.

I am having a little trouble following your description of the problem so I may have it wrong.

I have the idea that when the alarm is triggered, a mechanical wheel (possibly spring driven) operates a relay to send the location of the alarm and after sending, it ends up on rather than off.

You want to connect an external horn and light to the system activated by the same relay so it will also turn on and off with the location information and (undesirably) state on at the end.

Is this correct?
 

Yaakov

Joined Jan 27, 2019
1,612
When I lived in Boston, I worked with the Red Cross and BFD. The fire alarm system there involved pull boxes that required winding, and it would send its ID via pulses to "Fire Alarm" and over the air on their dispatch frequency.
 

Thread Starter

smokey4111

Joined Jan 29, 2019
8
Welcome to AAC.

I am having a little trouble following your description of the problem so I may have it wrong.

I have the idea that when the alarm is triggered, a mechanical wheel (possibly spring driven) operates a relay to send the location of the alarm and after sending, it ends up on rather than off.

You want to connect an external horn and light to the system activated by the same relay so it will also turn on and off with the location information and (undesirably) state on at the end.

Is this correct?
 

Thread Starter

smokey4111

Joined Jan 29, 2019
8
yes want to add a relay for the 110 vac because the alarm was low voltage for the teletype system FORGOT TO TELL YOU ALL THIS IS FOR MY MAN CAVE, Thanks
 

marcf

Joined Dec 29, 2014
259
Is this the equipment that you have?

https://www.gamewell-fci.com/CatalogDocuments/CS-2261.pdf

You should be able to activate a relay connected in series with the loop. You would need to provide a voltage on the loop to cause 100ma of current. This thing also has the ability to 'code' to ground as well.

I worked on these (among other things) until I retired.

If this is the kind of box that you have, I should be able to help you.
 

marcf

Joined Dec 29, 2014
259
With no 100ma loop current, the box should code from either 'line' connections to the common connection. At the end of coding either line should disconnect from ground if the top three (L1 GND L2) screws in your photo are connected.

I am sorry, but I gave wrong info. The box will continue to run on an open circuit until it runs down. At this point it will place a ground on the loop so it my be identified and restored to normal operation after the open circuit is restored to a closed one.

I suppose you could place your 120vrms relay coil in shunt (in parallel with the coding contacts). You would have to provide some means of providing the 100ma of loop current however.

Also you may 'trip' the box with a external connection without having to pull the handle.
 
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