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Discussion Starter · #1 · (Edited)
I am in the midst of troubleshooting a Gamewell type coded fire alarm system. It is a 100 milli-amp system using a central power supply for all 4 loops. One loop does not work, not tripping the notification circuit.

Is anyone familiar enough with a 100 ma system to give a some ideas on how to go about the system. I will give particular voltages and other items needed when I receive some replies. Thanks in advance,
JJB
 

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Capra Aegagrus
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I guess the answer might be in here somewhere.
Ditto. I was waiting to see if anyone had a pat answer, because that's as good as I could do with the info given.

If JJB can give us more details on what specific setup he's dealing with, it shouldn't really be all that difficult to work up a troubleshooting sequence. Those systems just aren't generally all that complex.
 

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Discussion Starter · #4 ·
Gamewll

Thanks for replying,

The system is a municipal loop type system where each of the 4 loops are powered via a central station. Each loop reacts to any pull station with a code wheel shunting the circuit on every stroke of the code wheel. The power to each loop drops to zero with every shunt.

The notification circuit seems to run off of a relay inline with the initiation loops. This relay is always powered until a shunt turns off the power to the relay. The horns and single stroke bells are on the N/O contacts of the relay,

What confuses me is the power to each loop is at a different voltage. One is at 27 VDC, another @ 75 VDC and the 3rd is @ 86 VDC. The loop that is the trouble one checks out @ !27 VDC. It seems to me that if I put a relay inline with the initiation circuit to operate the Notification circuit power supply, I will fry the relay. Is this a proper way for the system to act?

Thanks in advance,
JJB
 

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Capra Aegagrus
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I have to admit to being totally without a clue on this with the information given. Can you, either with info from the Gamewell website or just by physical examination, show us a schematic of the circuit(s)? Model numbers? This stuff isn't really all that complex if you have all of the information.

Just curious, because your description of the situation seems a tad off of what i would normally expect, where are you? Can't quite pin it down, but you don't sound quite like the average USA citizen.

That's why we prefer that people include their location in their profile when registering for this site. :thumbsup:
 

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Capra Aegagrus
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Ah. I have in-laws who live there. They're not your average USA citizens. :laughing:

Anyway, if I had schematics, I could probably help. My experience is mostly with consumer electronics, 2-way radio and fax machines, but the troubleshooting is pretty universal. Unfortunately, I never even heard of Gamewell until you posted here.
 

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The voltages are different because each loop has a different resistance. The 100mils has to be maintained (or close to it). The # of street boxes and masterboxes plus the distance of wire will give eack ckt it's own resistance. The voltage can be increased or decreased as needed for the ckt to maintain the 100mils. How are your ground readings? What are you getting at the power supply? Have you opened the ckt in the town and read from the middle of the ckt? How does the ckt operate in ground return on both sides? Last but not least for godsakes dont use a fluke meter to troubleshoot. Get a decent simpson 260 - you will have much better results. Also make sure the relay has the correct coil if you are placing it on the loop. Think about using the coil relay to trip a wheelock booster using the cc1 dry contact. That way you can supervise the wiring to the NAC ckts in the station or where ever you need.
 

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Hello, I have a problem with one of the five Gamewell coded signal, 100ma circuits that is still in use as the primary fire alarm reporting system. They are all of the shunt trip type of course except for the manual only ones in the system. I have had a hard time nailing down the location of the problem. Have you ever seen an instance where the loop has a ground on the system but is still operating almost normal if you cut out part of the loop, or reduce the total resistance of it. It is still at 6.5 mega ohms. I don't see how it is working at all. Please Help
 

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Discussion Starter · #10 ·
I have had a hard time nailing down the location of the problem. Have you ever seen an instance where the loop has a ground on the system but is still operating almost normal if you cut out part of the loop, or reduce the total resistance of it. It is still at 6.5 mega ohms. I don't see how it is working at all. Please Help
On the system I have worked on recently, the loops can go down to about 75MA before service seems to be affected. I had one pesky loop that showed about 74ma after we had changed out all of the wire feeding the circuit( About 1 mile in length). It was a mess until we changed out the Master box and the circuit went to 97MA.

Check the Master box for high resistance on the auxiliary loop, that seems to be the place to go after you have checked the wire feeding the circuit for grounds.

Hope this helps,
JJB
 

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Gamewell Shunt trip 100ma closed loop circuit

Well I have found out that one of the major problems I was having was just as oldalarmguy said, Do not use a digital Fluke meter. I now own a Simpson 260, I do not see how I got this far with out it. The other discovery was the two different sets of varistors in the system located just below the decoder and also in junction box before the loops leave the fire bay. Since they had been overheated due to the unfavorable condition of the circuit, there would always be about 8ma of current as a box would come in (or while the contacts in the coded alarm were pushed open). Once I replaced these with new ones rated at 10Amps, everything except the furthest part of the loop works great. If I add the rest in which is exactly 64 ohms the voltage that was at 35vdc becomes around 5.4vdc not nearly enough to operate. What I need to know is if anyone knows how much is resistance is acceptable on the shunt trip master box on the main circuit hook up. I have read them to be anywhere from 9 ohms to upwards of 35 ohms. Could it be just pitted or dirty contacts in the system overall. The entire loop was working up until about a month ago. Now only with the last part cut out. I know to check the aux. circuit to make sure it is below 30 ohms. Thanks for any advice you have!:thumbup:
 
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