Federal Model 28 wiring help please........

TonyT

Junior Member
There are TWO terminals on the top. The original photo I used for reference did not appear to be using both small terminals on top so I did not utilize that layout. So it soinds like I will need to correct the two on top plus swap the two large terminal connections, correct?
 

Skip Goulet

Passed Away
TonyT said:
There are TWO terminals on the top. The original photo I used for reference did not appear to be using both small terminals on top so I did not utilize that layout. So it soinds like I will need to correct the two on top plus swap the two large terminal connections, correct?
Right, Tony. Switch the two big cables. Looking at the solenoid from the back: Left big terminal is for siren cable; Rt goes to battery. Small terminals: left goes to switch and from switch to hot. Rt. terminals goes to hot. That should do it for you. Make sure you haven't damaged the solenoid due to the cable reversal.
 

Torpedo

Registered Member
Skip Goulet said:
Right, Tony. Switch the two big cables. Looking at the solenoid from the back: Left big terminal is for siren cable; Rt goes to battery. Small terminals: left goes to switch and from switch to hot. Rt. terminals goes to hot. That should do it for you. Make sure you haven't damaged the solenoid due to the cable reversal.
Um,...er,........small terminals, two hots?


One small terminal needs grounded and the other is switched hot from switch. Matters not which is which. I don't think it matters on the secondary (large cables) either. This shouldn't be this difficult. Ask John Marcson or Mtn man to post a diagram. I don't know how.
 

Skip Goulet

Passed Away
Torpedo said:
Um,...er,........small terminals, two hots?
One small terminal needs grounded and the other is switched hot from switch. Matters not which is which. I don't think it matters on the secondary (large cables) either. This shouldn't be this difficult. Ask John Marcson or Mtn man to post a diagram. I don't know how.
I disagree, Dennis. The ones we've used, the small left terminal on the siren side, like you said, goes to switch and then to hot. But the right terminal goes right to the big "hot" stud that goes to battery. The only ones I've seen grounded are the ones that have a single terminal on top that are used when they hook to the horn ring. Could be different type of solenoid, though.
 

TonyT

Junior Member
Looks like the only mod was to use the second small post on top as a ground to the (-) battery post. The switch isnt finalized but it did power up and engage the siren. Thanks to all!
 

Skip Goulet

Passed Away
TonyT said:
Looks like the only mod was to use the second small post on top as a ground to the (-) battery post. The switch isnt finalized but it did power up and engage the siren. Thanks to all!
So where's the video with audio? :)
 

TonyT

Junior Member
So, six years late. Came across this while I needed to reference it along with my installation for a project a friend is working on. Enjoy!

edit-sorry, wont accept my phone file.... ;(
 
Last edited:

leslawman

New Member
And here in 2020, I’m going to resurrect this post instead of starting a new one. I am the proud owner of a Federal Model 28 that I’m considering installing in my 2017 Expedition. The Expedition’s alternator is rated at 250 amps. Is that enough to power it with all the other electronics active on today’s modern vehicles? Next question: do I put the fuse between the battery and the solenoid or between the solenoid and the siren? Thanks. F0B39A46-7DE8-4197-A071-1EDEEB57A039.jpeg
 

jmamrak

Established Member
Always fuse closest to the battery. If you decide the alternator can’t handle the power there is a plan B. It is a complicated wiring setup but it can be done. I would go the “simplest first” method. Especially because the 28 is low draw. I believe mine was below 50 amps.
 

shues

Lifetime VIP Supporter
Consider that when this siren was new, alternators were rated to produce tens of amps, not hundreds.

The battery will provide whatever current a mechanical siren draws, even if the mechanical siren's startup current is higher than the alternator's rated output, as this current draw is only seen briefly. A mechanical siren's motor is a lot like a starter motor. The alternator will recharge the battery, just as it does after the battery provides whatever current the starter draws, as this startup current, too, is much higher than any alternator's rated output.
 

leslawman

New Member
Makes perfect sense Shues. Thank you. I guess now the hardest part is to find a place to mount the thing! There’s just not much (any) room under the hood without having to fabricate something between the grill and radiator... I guess if it was easy, anybody could do it!
 

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