Your are so correct! I like to show my students designs that are complicated versu simple solutions so they can understand the complexities when developing low and high tech products. As you noted, sometimes simple solutions can become quite large when trying to make them fit across the board problems.
I am sorry about the error on the parts list for the relay. Your attention to detail is very good. I also realized from the last post that I show the relay switching the neutral side of the second lamp. It should be shown switching the hot side, like the primary light switch, which is standard practice in residential construction.
The on/off cycles for the florescent lamps are no greater than the lighting on/off cycles for any other workshop. This was just a fun way to keep row over the door off when the door is up and I am working on things. It is, however, good know about the cycling characteristics of the florescent lamps.
The relay listed in the parts list is not the one actually used in the project. The one actually used is an Opto-22 and is for AC loads. The one listed in the parts lists is from Crydom and is for a DC load, not AC load as in this application. Furthermore, it has a maximum rating of 60 VDC. The input control voltage is 90 - 280 VAC which is no good either because it is being driven by the rectified output of a 16 VAC source.
You should also be aware that the life span of flouresent lamps are affected by the number of times you switch them on. This is a quote from Wikipedia:
"If the lamp is installed where it is frequently switched on and off, it will age rapidly. Under extreme conditions, its lifespan may be much shorter than a cheap incandescent lamp. Each start cycle slightly erodes the electron-emitting surface of the cathodes; when all the emission material is gone, the lamp cannot start with the available ballast voltage."
#1) I guess in the overall scheme of things, the few watts per day that the bell transformer uses are not going to bring down your local power grid. Since those transformers are fairly high impedance, it probably doesn't matter one way or another. IF it was my circuit design, I would probably have put it on the swiched side of the AC circuit, just because that's the way my brain is "wired".
#2) What I was referring to was placing the SSR on the low side of the AC circuit, not the control relay. Whenever I've used SSR's in control applications, I've always fed them, and taken the loads from them.
#3) I'm NO attorney either, but in today's litigious atmosphere, where INsurance companies generally contrive to void policyholders' claims, seeing this circuit made me take pause. YOu can bet your bottom dollar that some over-zealous investigator COULD insert a sentence or more about your circuit in an attempt to deny a claim. Although I've never wired anything of my own design into the electro-mechanics of our houses (and I've thought of many applications over the decades!), I just question the efficacy of doing so now. In my younger years I've totally wired several houses from the "pole" to the last outlet, so I did have intimate knowledge of acceptable wiring practices.
I considered switching the transformer but thought that cycling power to it might be harder on it than leaving it on. I ended up thinking of it as another door bell transformer (it is), which stays on all the time.
I used the relay and switched low voltage (16 V) to prevent exposure to line voltage out on the garage door track.
I don't know about the insurance issue. I designed it to be as safe as possible with line voltage contain in the junction box. The low voltage circuit is like a door bell circuit.
Truchard will be presented the award at the 2014 Golden Mousetrap Awards ceremony during the co-located events Pacific Design & Manufacturing, MD&M West, WestPack, PLASTEC West, Electronics West, ATX West, and AeroCon.
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