Model 55 Resonating Horn Wiring Diagram

Aug 2, 2022
24
Maine, USA
I recently bought a second-hand Federal Signal Model 55 110/120v (according to the metal plaque on the unit) resonating horn. From searching all over, no one has any available diagrams that show or tell what wires are responsible for what (i.e., ground, neutral, power, etc.) and the videos I've found on Youtube have not described how to wire it at all.

The unit I bought has 3 wires sticking out, black, yellow, and blue. From some searching It appears that this resonating horn is AC powered, as far as I could find out.

Any help with getting the diagrams and how to operate this would be most appreciated!
 

JohnMarcson

Administrator
May 7, 2010
10,971
Northwest Ohio
I don't see exactly what you need but it looks like there are many voltages including higher voltage dc ones. The colors you describe sound like multi phase AC or High volt DC. There does not seem to be a standard wire color though as you noted. Perhaps you got an industry or region specific one. Do you have a pic of the tag?

120vac should be black, black, ground/green
Screenshot_20230528-184216.png


Screenshot_20230528-183343.pngScreenshot_20230528-183320.png
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Last edited:
Aug 2, 2022
24
Maine, USA
Finally got around to getting pictures of my unit. It's a lot older looking than the one you provided
I don't see exactly what you need but it looks like there are many voltages including higher voltage dc ones. The colors you describe sound like multi phase AC or High volt DC. There does not seem to be a standard wire color though as you noted. Perhaps you got an industry or region specific one. Do you have a pic of the tag?

120vac should be black, black, ground/green
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View attachment 244731View attachment 244732
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Finally got around to getting pictures of my unit. It's a lot older looking than the one you provided.
 

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JohnMarcson

Administrator
May 7, 2010
10,971
Northwest Ohio
Finally got around to getting pictures of my unit. It's a lot older looking than the one you provided

Finally got around to getting pictures of my unit. It's a lot older looking than the one you provided.
I think you have some fading, but it looks like a 120vac 60hz horn. You should be good.

Looks like green ground, white neutral, and black line/hot; just discolored. I'd go full send and pop a 3 prong plug on there. Remember; white to silver terminal, black to gold terminal and green to green in the plug. Maybe plug it in to a switched power strip for good measure.
 
Aug 2, 2022
24
Maine, USA
I think you have some fading, but it looks like a 120vac 60hz horn. You should be good.

Looks like green ground, white neutral, and black line/hot; just discolored. I'd go full send and pop a 3 prong plug on there. Remember; white to silver terminal, black to gold terminal and green to green in the plug. Maybe plug it in to a switched power strip for good measure.
So based on everything so far, green to ground, white to neutral, and black to hot (power)? The one thing I don't get though is that mine has a yellow wire and not a white one, not to mention the example you showed was black, black, green. Also, where would I even get a plug to wire this up to?
 

JohnMarcson

Administrator
May 7, 2010
10,971
Northwest Ohio
So based on everything so far, green to ground, white to neutral, and black to hot (power)? The one thing I don't get though is that mine has a yellow wire and not a white one, not to mention the example you showed was black, black, green. Also, where would I even get a plug to wire this up to?
Home Depot sells male plug ends, or you can sacrifice an extension cord. That yellow looks like a discolored white to me. If you hack an extension cord you just connect like colors, keeping in mind your yellow is likely white IMHO. White, black and green are the standard US colors. But sometimes 120vac stuff that you have two blacks and it means they are non-polarized and interchangeable generally; treat one as a white. If you don't have any old extension cords, I would just get a male plug end and hook the "yellow" (discolored white) to the silver screw, the black to the the gold screw, and the green to the green screw in the plug.

Something like this should work.

I would plug it into a power strip with a switch and a build in breaker to be safe. Also keep in mind bad, cracked, or reversed wires could make the housing live, so be careful.

These horns were made in so many setups that they don't even bother with wire color schematics in their literature. Keep in mind 120vac is not something to be played with.... it ain't 220 or 460, but it isn;t 12vdc either. Keep your connections clean and strip down to good wire. I have some Federal buzzers and 120vac lights and some have two black and a green, others black, white and green. I also have seen the white get yellowed.

 
Last edited:
Aug 2, 2022
24
Maine, USA
Home Depot sells male plug ends, or you can sacrifice an extension cord. That yellow looks like a discolored white to me. If you hack an extension cord you just connect like colors, keeping in mind your yellow is likely white IMHO. White, black and green are the standard US colors. But sometimes 120vac stuff that you have two blacks and it means they are non-polarized and interchangeable generally; treat one as a white. If you don't have any old extension cords, I would just get a male plug end and hook the "yellow" (discolored white) to the silver screw, the black to the the gold screw, and the green to the green screw in the plug.

Something like this should work.

I would plug it into a power strip with a switch and a build in breaker to be safe. Also keep in mind bad, cracked, or reversed wires could make the housing live, so be careful.

These horns were made in so many setups that they don't even bother with wire color schematics in their literature. Keep in mind 120vac is not something to be played with.... it ain't 220 or 460, but it isn;t 12vdc either. Keep your connections clean and strip down to good wire. I have some Federal buzzers and 120vac lights and some have two black and a green, others black, white and green. I also have seen the white get yellowed.

Alrighty, I'll try it out and see if it works or not. Thanks for the help!
 

JohnMarcson

Administrator
May 7, 2010
10,971
Northwest Ohio
Alrighty, I'll try it out and see if it works or not. Thanks for the help!
I just looked at my older federal klaxon. It has similar wires, white is very yellowed. I just spliced it to an extension cord my wife won't miss, worked fine.

Just use a power strip. When ever I do dodgy 120vac $hit I do that so I can unplug it, turn it off, and it has a built in breaker. But you should be fine. I see no other possible way to wire it. The newer ones aren't even polarity sensitive (two black wires). If you plug it in and nothing or something other than the desired results occur, unplug it.

Let us know how you do.
 
Aug 2, 2022
24
Maine, USA
I just looked at my older federal klaxon. It has similar wires, white is very yellowed. I just spliced it to an extension cord my wife won't miss, worked fine.

Just use a power strip. When ever I do dodgy 120vac $hit I do that so I can unplug it, turn it off, and it has a built in breaker. But you should be fine. I see no other possible way to wire it. The newer ones aren't even polarity sensitive (two black wires). If you plug it in and nothing or something other than the desired results occur, unplug it.

Let us know how you do.
Thanks for the help! It worked nicely. I may have to redo the 3 wires at some point since the insulation is so junked that it just crumbles at the slightest touch. I also have to fix the bent trumpet portion of the horn at some point since it could be making it sound off.
 
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Aug 2, 2022
24
Maine, USA
I just looked at my older federal klaxon. It has similar wires, white is very yellowed. I just spliced it to an extension cord my wife won't miss, worked fine.

Just use a power strip. When ever I do dodgy 120vac $hit I do that so I can unplug it, turn it off, and it has a built in breaker. But you should be fine. I see no other possible way to wire it. The newer ones aren't even polarity sensitive (two black wires). If you plug it in and nothing or something other than the desired results occur, unplug it.

Let us know how you do.
Update on the unit.

I popped it open to see why it sounded off, and well just take a look at the pictures.

Can you tell me or provide any sort of pictures as to how it should look? Someone at some point had opened it up and messed with the wiring and put all of this weird looking powder-like stuff into it. You can also see in one of the pictures that the green wire was cut off and has been taped, which may explain why it sounds off. The other wires can be seen having been spliced at some point and then fixed with wire nuts.
 

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JohnMarcson

Administrator
May 7, 2010
10,971
Northwest Ohio
Looks like someone rewired it and it has a lot of corrosion. Start with a wire brush carefully.
 
Aug 2, 2022
24
Maine, USA
Looks like someone rewired it and it has a lot of corrosion. Start with a wire brush carefully.
Got most of the corrosion off without too much difficulty. The next thing I want to find out is where the green wire was suppose to be hooked up to. Does your model 55 have a similar looking design inside the unit?
 

JohnMarcson

Administrator
May 7, 2010
10,971
Northwest Ohio
Got most of the corrosion off without too much difficulty. The next thing I want to find out is where the green wire was suppose to be hooked up to. Does your model 55 have a similar looking design inside the unit?
The only one I saw opened up and up close had just two wires, it was also old, so it was either "2 prong" or the ground was removed. I assume a case/ground would be better than nothing. I'm not sure there were actual ground points, someone added a 3 wire cord to a 2 wire model probably. But again, i think the green earth is just a case/chassis ground; find a suitable screw.
 

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