I agree that putting tinned (or small strand untinned) copper wire under a screw is a bad idea, and putting it into one of those screwless push-in terminations is even worse. (I never use those, not even for the sort of wire they're designed for.) However, I can't really agree with your recommendation to use copper crimp sleeves instead. Most of these aren't designed to put under a screw either - in fact I don't believe I've ever seen any for that purpose sold at Lowe's similar stores around here. They may have the ones for screwless push-in terminations - I think they're mainly designed for speaker connections - but I sure wouldn't use one.
A solution that is readily available is a crimp on ring or flanged fork crimp on connector. Make sure you use the right size for your wire gauge, and if you're worried about stranded wire pulling loose, you can solder it to the connector as long as you're careful not to get solder on the part that goes under the screw.
As for getting the wire in and out of a box, you may be able to use a regular strain relief grommet appropriately sized for the wire if the enclosure walls aren't too thick.
That's actually the second concern I had, and I immediately dismissed it.
When I was a young single guy in colllege and after I got out and started working, I had a habit of making myself a gourmet meal of Chili and hot dogs... I would make a big pan of chili and slice up ot dogs to throw into the pot.
When it was done cooking, I would serve myself whatever I wanted to eat that night, and the leftovers I just left on the stove.
The next day, I would just reheat what was left over and finish it off.
I have never had food poisoning in my life. I have been to a big barbecue where 20 out of 25 people that attended got food poisoning... I have also been to Mexico where literally the entire group got food poisoning... With the exception being me.
I always attributed my lack of being poisoned with my habit of continually exposing myself to all kinds of bacteria... My immune system was always up to the challenge.
The other question I had was this... What happens if you set that thing to go off, and then something happens to prevent you from coming home at the time you expected? Your timer would never shut off. It would simply be on forever... Or until your meal was a dried up mess completely baked to the bottom of the crockpot.
If I were you, I would just buy a Titan Controls Apollo 6 timer. Very easy to use, and quite cheap. (It has a suggested retail price of $14... But you can get them cheaper than that...)
You simply twist the dial to set the time on the timer. Then, when you want it to go off, you start filipping the switches down. There are 96 swithches, each switch is for 15 minutes. Flip the switches until you've got them flipped for as long as you want... Each four you flip means it will be on for an hour... Flip 16 of them down, and it will cook for 4 hours... BUT, when there are no more switches flipped, it will then turn the circuit back off. If you don't come home for days, it will repeat the cycle for 4 hours every day until you unplug it... But this is cheaper and just as easy as your solution... And a bit safer, too...
And, you don't have to build a thing... Just plug the timer in, and plug the crock pot into it. It's rated at the full fifteen amps... Which is plenty.
The Intermatic timer that I use for my christmas lights would also work. And it has the same ability to turn the circuit back off. I bought that timer 20 years ago, and it's still working perfectly after running my christmas lights every year for twenty years. I can't imagine that it cost me $10... Probably $6... But that was twenty years ago...
I just don't really think that setting a timer to start cooking something and it has no function to turn the cooker off is really all that good an idea...
I'm probably going to be accused of missing the spirit of this submission, but why not use a store-bought timer? I know I'm not the only one to suggest this, and for less than $10, they are very readily available:
Another solution to the slow cooker dilemma is Hot-Logic, with Hot-Logic it not only perfectly cooks your food but holds it at a pathologically safe temperature all day without boiling, burning or drying out your meal. We use of these at work and I gotta tell ya this thing is really great, I've seen guys leave stuff in for twelve hours if not longer with out issue...
Never solder-tin stranded wires that will be placed under a screw or set-screw! This is against UL regulations and other certification agencies for a GOOD REASON! Over time, the soft solder will deform and the compression that once existed will lighten up. At some point the joint can even become loose. When this happens, the joint will become resistive and produce heat, or even arc, becoming a fire hazard. The same applies for so-called screwless termination, where wires are inserted into a hole in the device, where a sharp edge will contact the conductor. There are soft copper "tubes" that can be placed over stranded wires and compressed into place, that are designed specifically for holding stranded wire under set-screws and screw heads. These can even be found at Lowes and Home Depot, they are not exotic and hard to find. It may also be advisable to use a silicone dielectic grease on the bare copper to prevent any potential of oxidation over time. One other thing, Extension cord wire is NOT rated to be squezed in a screw tightend strain releif-compression fitting, as illustrated. The fitting shown is designed for Non Metallic Jacketed solid core house wire, also known generically by the brand name Romex. If you are going to apply squeese perssure to lamp cord, you are asking for trouble as the insulation deforms and can eventually be penetrated. It would be best to use a flexible insulating sleeve over the lamp cord to protect the jacket material and distrubute the forces such that the likelyhood of eventual failure is reduced. Food safety......Foods should not be kept at room temperature for very long. That is a different subject that electronics, and not specific to the controller, but I for one, would not want anything I'm going to eat to be out at room temperature for an extended period of time before cooking would begin. I suppose if the food was frozen before being placed in the slow cooker, that might be partially acceptable, but I question the need for a delay start of a slow cooker in the first place, simply on basis of food safety protocols. Just putting your frozen foods into a slow cooker and placing it on LOW setting will bring the temperature above the minimum for bacterial safety, and give you well over 8 or 12 hours of time without over-cooking. They make heat settings on most slow cookers for a reason.
A caveat for using this device - be mindfull of the types of foods used and the length of the delay. Leaving meats or other perishable foods at room temperature while waiting to start the cooking cycle is an open invitation to some nasty bacterial growth and subsequent illness. Food poisoning is, at best, no fun and can be deadly!
One minor problem with delaying the start of the slow cooker is really quite small...Bacteria.
If a food product sits too long at room temperature, bacteria which can and often does cause food borne illness can multiply, add to that the slow ramp up to cooking temperature and the relatively low cooking temperature, specially at the low and slow setting of many slow cookers and you have a wonderful incubator.
Remember, it is usually not the actual microscopic creature which causes the illness, it is the toxins which the little assassins create which make you ill (or worse).
Delay the start of cooking as little as possible and get the food from Refrigerator temperature to cooking temperature and back with alacrity, and you will minimize the possibility of creating a food borne Frankenstein...Beans...Frankenstein...Beanie-Weenies and a Stein of Beer...Gotta get that Slow Cooker out for Beans...
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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For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.