Scored A Sentry SS3/Defender

[Travis]

The unit was from Tuttle, OK and was removed when they upgraded to ASC T-121's. *For those of you who participate on social media, you likely already know about this siren, but you'll notice the siren is looking much better in the pictures below. The siren had sat in a scrap pile for quite some time and was full of dust, mud, and many many dead hornets. The siren head has since been cleaned out, and is in much better condition than I thought previously. There is almost no rust to speak of, and most of what you see left over as far as crud is just leftover mud.*

What I have discovered:

Not long after my family became an internet faring people, I happened upon the old siren board of ancient times, (Jason's board) and it was shortly after my joining that did Sentry come up with the plan for a new rotating siren. IIRC it was either Sirens for Cities, or Sentry Siren who actually broke the news. The new concept was tentatively named the SS3. In a marketing effort, Scott (of Sentry) or Ed (of Sirens for Cities) actually approached the members of the old board with a naming contest. I don’t recall the specifics, but we all know the outcome: Defender.

The Defender was Sentry’s first foray into the world of rotating sirens, and among the first of their experiments with what is now a very popular DC-powered siren lineup. Digging through board archives it seems that this venture started with the request from a municipality for a rotating Sentry product. I couldn’t positively figure out what town that might have been, but if they ended up liking what Sentry produced, that town is probably Tuttle, OK. How do I know this? Well I really don’t, except for the fact that serial number on mine happens to be R001. I need try and get with Sentry, but I think I may have, by chance, acquired the first production model ( even prototype?) SS3/ Defender.

There weren't a lot of these sirens produced, and I would definitely consider them to be uncommon if not rare. This specific unit is definitely unique in that it is 48VDC only. It has a small battery (ahem, Delta welding box) box, and a very primitive looking charging system. It doesn't have a transformer rectifier, merely the 48V contactor and CD&F controller. I don't know if they made more than one or two of them before switching to a 72VDC system. All the literature I have on the Defender advertises 72VDC, or AC options. Looking at Google SV, the one in Slater, IA has the big battery box, and I would assume the one in Argos, IN is as well. There are some other minor design differences I have noticed as well, mainly with how the back of the motor housing attaches to the top of the turntable, the intake cone, and rotator housing fasteners. I could not find an actual date on the siren head or motors, but the manufacturing date inside the battery box says 2001. So I think it's safe to say this siren is from that year. While small, this siren isn't flimsy, and it isn't by any means light. I had to disassemble it in the bed of my truck piece by piece to get it light enough to unload without a crane. The frame, and most of the pieces are 1/4" steel. The base of the siren is 26"x26." Just the head weighs 400lbs. The good thing is, I was able to fashion some wheel trucks to mount it to, so it rolls around the garage rather easily now.

The tag on the chopper motor doesn't have a horsepower rating listed, but the advertisement I have from Sentry lists it as using an 8HP motor. I have no idea what the rotator motor makes, but it is pretty small and also runs off 48VDC. The rotor/stator assembly is the same as all other large Sentries. It's their standard 8 port "tall." They've used these on everything 5V and higher, up to the 20V series.

Probably the most fascinating part about this siren is how Sentry designed the rotation drive. The chopper motor sits suspended in a cage on a rather large circular steel plate which is attached to the rotation drive shaft with 5 bolts. This plate sits on top of a turntable, which also forms the top of the rotator housing. The main rotation drive shaft runs through a set of brushes, and terminates into what i believe is a planetary gear drive. The gear drive is connected to a gear reducer box, and finally couples with the actual rotator drive motor. It looks to be almost over engineered. It would take some extremely strong winds to keep that siren from rotating. I do find it interesting that Sentry has both the chopper and rotator drives wired together. They are in parallel so they are both 48V, but there is no provision onboard to operate each component independently. It wouldn't be difficult do, but would require another motor contactor and additional wiring infrastructure.

I'll try to explain the pics as best I can. Please forgive the less than ideal lighting. I plan on doing a walk around video when I have it cleaned up a little more. I plan on giving this a decent workover, and replacing and refinishing exterior parts that need it. I don't think this will be living outside anytime soon, though I do plan on sourcing a new battery box and chargers. The wiring looks pretty solid, so there won't be much to do there, but the CD&F controller is in pretty rough shape. It was working when removed but it has a bunch of foreign debris inside.

[Travis]

Forgot to ad a picture of the ID tag. In case you can't read it clearly, it says:

MOT: WIN
NO: R001
PH: *
V: 48DC
A: *
HZ:*
MOD: SS3

IMG_6864.JPG (474.42 KiB) Viewed 4706 times

I've always liked how they use the the "Sterling Quality Siren" ID tags, even on brand new sirens.

[Model L]

Thats awesome! really great to see one of these things! keep us updated.

[Darley Champion]

Dear God... talk about a score! If this happen to be confirmed that it is the 1st SS3 Defender made.. Then you have more than scored a Defender!

[JasonC]

For all the newcomers on the board, Sentry actually held a contest on The Siren Board to name the siren! The winner received one of their smaller sirens from them. It was a pretty cool little contest.

[Brendan W]

Nice score!

I am curious though, could R001 possibly mean this is the first one?

[Travis]

Nice score!

I am curious though, could R001 possibly mean this is the first one?

Precisely my thoughts. That and the other small differences like running voltage and some of the bolt locations that hold on the housings. Newer Defenders are a little different/more secure looking.

[SirenMadness]

What a unique machine, I always liked how Sentry pressed those three ring grooves into the sheet metal of the horn. Interesting to see how much space is left over in that rotator housing.

[freebrickproductions]

Great grab!

[siren fan]

Nice snag! I think there is one around the Durant, OK area if it hasn't been removed yet.