Relay contact ratings.

I have to say that during the time that I lived in the US, the medical care that I received was excellent and my co-payments were less than I pay back in Australia *BUT* I had an employer paying for my medical and pharmacy insurance. I was never quite comfortable though that, should I have needed expensive treatment, my HMO would have the final word on that treatment.

At to the poor, my wife used to volunteer at the emergency room at the local hospital she had quite a few horror stories. I did my bit to fund the programs for the poor, 5 1/2 years of maximum social security payments that I am not going to see a penny of.

I have a friend there who is retired (not by choice) who has to spend a fair proportion of his income on medical insurance, and, even then, when his wife had a bad car accident, he still had some really big bills to pay.

the closer the inside temperature of the fridge is to the outside temperatue the less work the compressor needs to do to circulate he coolant.

a warm evaporator means the compressor's input is at a higner pressure than normal and thus it needs to do less work to compress the gas enough to condense in the condenser,

--
?? 100% natural

--- Posted via news://freenews.netfront.net/ - Complaints to news@netfront.net

From context, I assume you meant "more" in that last sentence.

The question is - does it matter? That is, will running the compressor when the element is warm do anything more than consume some extra electricity. I suppose it's no different from having the fridge turned off for a while, and then turning it on, but it may have some long term implications for the life of the compressor if it happens every six hours. I'm speculating - I don't know.

Sylvia.

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Still, are you going to put your hand on your heart, and say that some unknown relay in an appliance designed for 110VAC will be safe to use at

240VAC?

That aside, this subthread related to electronic defrost timers. They may not be using electromechanical relays at all, but semiconductor devices.

Sylvia.

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This is an interesting question. Whether the compressor starts immediately as the heater turns off, or waits a few minutes for the evaporator to "cool" , would make no difference IMHO.

The reason being that even if the heat is allowed time to dissipate from the evaporator before re-starting the compressor this heat is only going to dissipate into the freezer/ refrigeration compartment and if nothing else, warm the compartment and food slightly more. The compressor still has to work to remove this heat, as it is still in the cabinet, just in a different place.

It will just take longer for this dissipated heat to "come back:" to the evaporator and be removed via the normal refrigeration process. If turned on straight away, this heat is removed first, then the unwanted heat from the rest of the refrigeration cabinet, including the food within. Theoretically the instant changeover is better for the food from preventing this temperature rise , by admittedly a very very tiny amount that is certain to be irrelevant in this application.

If you were defrosting by a heater something like a heatsink or radiator that was being refrigerated to cool it, but was operating in open air and not in a closed cabinet, it would be slightly more beneficial from a power saving viewpoint to let the defrost heater's heat dissipate first before re-starting the compressor.

PS: this discussion motivated me to defrost the small fridge in the office. Thanks for that :)

What a mess.

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No, unless there was no choice but to keep the relay or device. In that case, I would at least examine the contact clearance and size and compare it to a known good relay that was suitable, or simply use the device to drive a relay that would do the job.

I wouldn't EVER blindly trust a solid state device designed to switch

110v on a 240v supply, unless again you could check the ratings of the SSR or SCR. Triac etc used, and ratings of any associated components such as suppressors, MOV's etc that might be involved.

You just reminded me of an actual situation where this happened.

I did come across this about 20 years ago, where a disco light control unit in a juke box imported from the USA ran from 120v, and ran 120v 15w bulbs that were unavailable in AUS, and blew often. There was an internal stepdown transformer fitted to provide the 120v needed for the entire machine.

They wanted to change it to 240v 25w bulbs, and I will admit they did look a hell of a lot better in the application than the 15's that were not very satisfactory in brightness.

We were unable to determine the specs on the triacs fitted as they only had a OEM part number on them, but converted it to 240v use by replacing the Triacs with BT139's and it worked well.

They were opto and physically isolated from the logic circuit, as well as having a separate mains rated connector and wiring at the opposite end of the board and outer casing so there was no problem with the safety aspect of the modification.

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yes, its a wonderful feeling. I understand over there they have draft legislation on the table to grab private pension funds (401K ?) and put them into gov bonds that will disappear as the country has its inevitble financial collapse.

Super is a scam in my book, unless you are close to the age of getting a payout.

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Sound like we should wire the whole fridge with sensors. But that's fine, thermistors are cheap. PIC32 can handle up to 16 analog channels.

BTW, i also have a busted microwave and fridge to play with. If only i have a robotic arm to move something from the fridge to the microwave and nuke it in the morning.

Given that our natural gas is 80% cheaper than electricity, and going lower. I might replumb the fridge with (gas) hot water pipes, with electromechanical water valves. Can i use plastic sprinkler valves for warm water? I can install the valves at the outlet, so they won't be too hot anyway.

Items made with the gray plastic for sprinklers isn't certified for indoor use. It is low pressure & low temperature rated and easy to break.

--
You can't have a sense of humor, if you have no sense.

=A0in

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After passing through the fridge, the warm water should be cold enough, if not too cold.

I know, i just rebuilt six of them and five were internally broken. But they are dirt cheap. The high quality replacement part should outlast the cheap factory part.

--- View with a fixed-pitch font.

This will give a 30 minute defrost cycle following a 6 hour freezing period:

|| || NC _______________________ _______________________ __ COOL_| |_| |_|

->| || |C . +-976K--|Rs MR|-------|------+-A / DIODE COIL]- -|K1 . | | | | | Y-+ | | O-> |NC . +-527K--|Rt | 10k +-B | +----+ | . | | | | | | | +-------->NO . +-1.0µF-|Ct Q13|-100nF-+ +-A | C . +------+ | | Y-+--1k--B NPN . | +-B \ E . +-A | NAND | . NAND Y-+ GND . +-B | . | | . | B-+ . +-Y NAND . | A-+ . 4060 | | . +------+ | Vcc | . +-887k--|Rs MR|-------+ | | . | | | | | . +-442k--|Rt | 10k | . | | | | | . +-0.1µF-|Ct Q13|-[100nF]--+---+ . +------+

K1's contacts are completely isolated, so if theyr'e connected into the rest of the fridge circuit the way the contacts on the motor driven timer were, everything should work like it did when the motor timer was in there.

No micro, no code, no programmer, no learning curve. ;)

-- JF

=A0in

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Added CAE, where some embedded designer are. We started with defrosting the fridge, perhaps controlling the microwave, and piping hot water through the fridge into the toilet. This way, we can defrost the fridge everytime we flush the toilet. However, in case we don't flush the toilet often enough, we need a PIC to monitor the toilet as well.

We are going to need defrost cycle counters, duration timers, target temperature, pipe temperature and toilet counters. So, first thing is to build the counters. I've decided to build with 42 LEDs and 4 595 shift registers. See:

http://173.224.223.62/pic32

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y.

Our biggest healthcare consumer is the gov't, and the more they buy, the higher they drive the cost--it's always easier to spend when you're spending someone else's money. Everything they do costs more.

I prefer competition, the same process that makes everything we do and buy get constantly better, and cheaper. E.g., computers. And, that's voluntary. The gov't universally does the opposite--they've got the wrong incentives and no controls. But, whatever we do, reality matters, not spin. That's why I chimed in.

-- Cheers, James Arthur

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Please ignore; I'm fixing the error.

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Competition has always been very successful in giving all of us more - for less. Coupled with the freedom to voluntarily buy or not buy what we want great things have been achieved

The opposite has never worked in the public interest.

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Done.

news/t4nfe7d1lnj35s2a3thchv3diqc827gq3g@4ax.com

Except for Apple...

-- Les Cargill

There are alternatives, you can voluntarily use Windows, Android, Linux etc, even a pen and paper, or you have the free choice to simply use nothing