If an RCM 3 isn't available make your own....

[CDV777-1]

Since I can't get an RCM 3 control box anywhere I decided to make my own. Well, not the whole box, just the panel. I'm using one of my empty RCM boxes I had to put it in. I was first going to make the electronic hi-lo relay unit that Adam has in his Thunderbolt section but I thought it would be far more hilarious to try to make a different version of the flasher unit that was used in the original RCM 3. Adam Pollak sent me some pics of his RCM 3 flasher and I worked from the general arrangement of the original but I used a 60 rpm syncronous AC motor to drive mine. The original RCM 3 flasher uses 2 cams and 2 switches but I'm using only one cam and one big microswitch with contacts rated at 20 amps at 240 volts. The porcelin fuse box and switch panel are from an old crappy RCM left over from Valley View that I scrapped for parts. Obviously I haven't wired it up yet. I just got it all put together. My flasher unit will have a 240-120 transformer on top of it to run the 120 volt timer motor since the panel will operate on 240 volts. I'm going to use a transformer out of an AR timer for that. I had the motor left over from my polarized light sign project I did a while back so running a 60rpm it will give the hi-lo cycle a half second cycle to each solenoid. I still have to tweak the cam a little to get the timing right. I can tell from the way the switch sounds now when it's running that the timing is a little uneven. Like the Mini-Thunderbolt all the material is scrap from work. Of course I made the panel and flasher at work. I've probably got about 6 hours in that. For those who wonder why siren stuff is so expensive from the manufacturers try making something like this and you'll see why. I hope to get the thing wired up this weekend.



My version of the flasher. Bracket on top is for the transformer.


Inside the flasher. A delrin cam drives the microswitch lever which switches every half second. Oil impregnated bronze bushings are the bearings for the motor/cam shaft. The flasher unit is 4 inches wide, 3 inches tall and 2-3/4 inches deep not counting the motor.

[Robert Gift]

I remember being fascinated watching the strange-shaped cam of my father's Peebles Volunteer Fire Department siren controller as it sounded the siren.

But now, why not do all siren signals electronically?

[CDV777-1]

But now, why not do all siren signals electronically?

Because it's boring. 8)

[Jim Z]

I remember being fascinated watching the strange-shaped cam of my father's Peebles Volunteer Fire Department siren controller as it sounded the siren.

But now, why not do all siren signals electronically?

like Eric said, it can be boring

also, in many cases, doing it mechanically can be more reliable. You could pull this off with a $200 Direct Logic PLC and about $50-100 worth of relays and contactors, but PLCs that cheap generally aren't rated for "high availability" applications. PLCs with that kind of robustness are pretty expensive.

[Robert Gift]

I agree.
Nothing is more fascinating than humming, turning, clicking mechanisms.
This is why I like clocks and steam locomotives.
(My favorite toy was a Tic-Toy Clock. See-through clock with colorful plastic gears. You can take it all apart, put it back together, wind it up and it keeps time!)
I recently acquired one from eBay.

My siren timer is a vacuum tube timer.
When an element inside the tube heats sufficiently, it opens it's contact in 180 seconds. Once open, I desiged the circuit to reset.

[CDV777-1]

Like I said in my post. I built my own version of the flasher primarily for the novelty and challenge of seeing if I could do it. I wouldn't ever put this thing into service unless I knew it was reliable enough to work every time. Maybe it will be, I don't know. Circuit-wise it will be the same as an RCM 3. Maybe I'll call it the CDM/RCM 3.

[CDV777-1]

Here's it is wired up. It actually works but I haven't tried it hooked up to a timer yet. I made the switch plate sticker with paint shop and printed it to some sticker paper. I turned the Thunderbolt RCM switch plate over and stuck the sticker paper to the back of it. My cam timing is off a bit so I have to take my "flasher" back out and tweak the cam until the time is even.

[texaschad25]

Hey Eric, did you paint the cabinet or is it an old one?? looks nice, and your set-up does too !!

[CDV777-1]

Hey Eric, did you paint the cabinet or is it an old one??

It's an old cabinet that I painted.

[EL1998P71]

Hey Eric and/or Board members,

Is hooking the AR timer to the RCM easy?
After looking thru the install PDF. I go cross eyed..

Here's the plan...

Single Phase compressor motor-acquired
Single Phase Rotator motor-Still needed
Chopper motor- acquired a working one
Three Phase RCM
AR timer

Will all these work together?