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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Mains off warning
Hello,
Does anyone know if there are any websites that have circuit diagrams for a mains warning alarm that sounds when the mains is off? We occasionally find that the circuit breaker trips for a circuit in the kitchen and if left unnoticed, the food in the freezer could thaw out. Thanks. |
#2
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Mains off warning
M.Joshi wrote:
Hello, Does anyone know if there are any websites that have circuit diagrams for a mains warning alarm that sounds when the mains is off? We occasionally find that the circuit breaker trips for a circuit in the kitchen and if left unnoticed, the food in the freezer could thaw out. Thanks. Aquarium owners use a device which does exactly what you require, I suggest you check out some fishkeeping websites. Ron(UK) |
#3
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Mains off warning
Plug a clock into the same circuit.
M.Joshi wrote: Hello, Does anyone know if there are any websites that have circuit diagrams for a mains warning alarm that sounds when the mains is off? We occasionally find that the circuit breaker trips for a circuit in the kitchen and if left unnoticed, the food in the freezer could thaw out. Thanks. -- Joe Leikhim K4SAT "The RFI-EMI-GUY"© "Treason doth never prosper: what's the reason? For if it prosper, none dare call it treason." "Follow The Money" ;-P |
#4
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Mains off warning
"M.Joshi" wrote in message ... Hello, Does anyone know if there are any websites that have circuit diagrams for a mains warning alarm that sounds when the mains is off? We occasionally find that the circuit breaker trips for a circuit in the kitchen and if left unnoticed, the food in the freezer could thaw out. Thanks. -- M.Joshi If you want to do it yourself, it would just need a mains voltage relay, and a battery powered alarm sounder ... Arfa |
#5
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Mains off warning
On Sat, 21 Jul 2007 17:38:12 -0400, Not me ) wrote:
On Sat, 21 Jul 2007 17:34:29 +0100, M.Joshi wrote: Does anyone know if there are any websites that have circuit diagrams for a mains warning alarm that sounds when the mains is off? We occasionally find that the circuit breaker trips for a circuit in the kitchen and if left unnoticed, the food in the freezer could thaw out. I would be inclined to keep a nightlight on the cricuit. I know you can buy specific freezer temp warning alarms at places like Lee Valley. http://www.leevalley.com/garden/page...120,33279&ap=1 Which would be good for when the power goes out *AND ALSO* when the _freezer_ goes out. |
#6
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Mains off warning
"M.Joshi" wrote in message
: Does anyone know if there are any websites that have circuit diagrams for a mains warning alarm that sounds when the mains is off? We occasionally find that the circuit breaker trips for a circuit in the kitchen and if left unnoticed, the food in the freezer could thaw out. If practical, consult an electrician about having the wiring and/or breaker changed. In most jurisdictions, it's permissible to have an outlet on a circuit dedicated to refrigerator or freezer use *not* be on a GFCI (which are the source of most "nuisance trips" such as this) for exactly this reason. Even if it isn't on a GFCI (which all kitchen convenience outlet circuits should be), the fact that it's tripping indicates that there's some problem -- perhaps the circuit is overloaded or the breaker is faulty. -- -------------------- Alan "A.J." Franzman Email: a.j.franzman [ A T ] verizon [ D O T ] net -------------------- |
#7
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Mains off warning
Allodoxaphobia wrote:
On Sat, 21 Jul 2007 17:38:12 -0400, Not me ) wrote: On Sat, 21 Jul 2007 17:34:29 +0100, M.Joshi wrote: Does anyone know if there are any websites that have circuit diagrams for a mains warning alarm that sounds when the mains is off? We occasionally find that the circuit breaker trips for a circuit in the kitchen and if left unnoticed, the food in the freezer could thaw out. I would be inclined to keep a nightlight on the cricuit. I know you can buy specific freezer temp warning alarms at places like Lee Valley. http://www.leevalley.com/garden/page...120,33279&ap=1 Which would be good for when the power goes out *AND ALSO* when the _freezer_ goes out. Hi... And though it doesn't address the specific question, put a frozen ice cube in a closed zipper bag in the freezer. Should the power fail while you're out long enough to warm the freezer's contents and then come back on, the ice cube will be a puddle of frozen water rather than a cube. Take care. Ken |
#8
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Mains off warning
"Ken Weitzel" wrote in message news:e4Ioi.137504$1i1.64362@pd7urf3no... Allodoxaphobia wrote: On Sat, 21 Jul 2007 17:38:12 -0400, Not me ) wrote: On Sat, 21 Jul 2007 17:34:29 +0100, M.Joshi wrote: Does anyone know if there are any websites that have circuit diagrams for a mains warning alarm that sounds when the mains is off? We occasionally find that the circuit breaker trips for a circuit in the kitchen and if left unnoticed, the food in the freezer could thaw out. I would be inclined to keep a nightlight on the cricuit. I know you can buy specific freezer temp warning alarms at places like Lee Valley. http://www.leevalley.com/garden/page...120,33279&ap=1 Which would be good for when the power goes out *AND ALSO* when the _freezer_ goes out. Hi... And though it doesn't address the specific question, put a frozen ice cube in a closed zipper bag in the freezer. Should the power fail while you're out long enough to warm the freezer's contents and then come back on, the ice cube will be a puddle of frozen water rather than a cube. Take care. Ken That's a novel idea Ken, but I reckon that the freezer would have to be off for longer than the average outage, here in the UK at least, for the ice cube to melt. Most freezers will hold up for getting on for 24 hours I believe, provided you don't disturb them by opening the door. Arfa |
#9
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Mains off warning
On Sun, 22 Jul 2007 21:13:49 GMT, Arfa Daily wrote:
"Ken Weitzel" wrote in message news:e4Ioi.137504$1i1.64362@pd7urf3no... Allodoxaphobia wrote: On Sat, 21 Jul 2007 17:38:12 -0400, Not me ) wrote: On Sat, 21 Jul 2007 17:34:29 +0100, M.Joshi wrote: Does anyone know if there are any websites that have circuit diagrams for a mains warning alarm that sounds when the mains is off? We occasionally find that the circuit breaker trips for a circuit in the kitchen and if left unnoticed, the food in the freezer could thaw out. I would be inclined to keep a nightlight on the cricuit. I know you can buy specific freezer temp warning alarms at places like Lee Valley. http://www.leevalley.com/garden/page...120,33279&ap=1 Which would be good for when the power goes out *AND ALSO* when the _freezer_ goes out. And though it doesn't address the specific question, put a frozen ice cube in a closed zipper bag in the freezer. Should the power fail while you're out long enough to warm the freezer's contents and then come back on, the ice cube will be a puddle of frozen water rather than a cube. That's a novel idea Ken, but I reckon that the freezer would have to be off for longer than the average outage, here in the UK at least, for the ice cube to melt. Most freezers will hold up for getting on for 24 hours I believe, provided you don't disturb them by opening the door. Well, that was his (unstated) intent: If the ice cube is still "sound", then the freezer contents are probably sound. If you find you have a frozen "puddle", then the freezer was off long enough to ruin the stored contents. Jonesy |
#10
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Mains off warning
"Allodoxaphobia" wrote in message ... On Sun, 22 Jul 2007 21:13:49 GMT, Arfa Daily wrote: "Ken Weitzel" wrote in message news:e4Ioi.137504$1i1.64362@pd7urf3no... Allodoxaphobia wrote: On Sat, 21 Jul 2007 17:38:12 -0400, Not me ) wrote: On Sat, 21 Jul 2007 17:34:29 +0100, M.Joshi wrote: Does anyone know if there are any websites that have circuit diagrams for a mains warning alarm that sounds when the mains is off? We occasionally find that the circuit breaker trips for a circuit in the kitchen and if left unnoticed, the food in the freezer could thaw out. I would be inclined to keep a nightlight on the cricuit. I know you can buy specific freezer temp warning alarms at places like Lee Valley. http://www.leevalley.com/garden/page...120,33279&ap=1 Which would be good for when the power goes out *AND ALSO* when the _freezer_ goes out. And though it doesn't address the specific question, put a frozen ice cube in a closed zipper bag in the freezer. Should the power fail while you're out long enough to warm the freezer's contents and then come back on, the ice cube will be a puddle of frozen water rather than a cube. That's a novel idea Ken, but I reckon that the freezer would have to be off for longer than the average outage, here in the UK at least, for the ice cube to melt. Most freezers will hold up for getting on for 24 hours I believe, provided you don't disturb them by opening the door. Well, that was his (unstated) intent: If the ice cube is still "sound", then the freezer contents are probably sound. If you find you have a frozen "puddle", then the freezer was off long enough to ruin the stored contents. Jonesy Yes, I understood that ... I was just making the point that if the power went out long enough for that to actually occur, then there's a good chance that it wasn't going to be coming back on at all before you got back from your trip or whatever. If it had gone out for that long, in the UK at least, the chances are that it would have been as a result of some major event, that you would probably have heard about on the news anyway. The last time my power went out for more than an hour, was probably around about 1980, soon after we moved to this street, and a transformer on an overhead pole, actually quite close to where my current house is, but which was then in an open field, was knocked out by a direct lightning hit, that I was lucky enough to actually see happen. But yes, if the power was lost for perhaps 2 or 3 days whilst you were away, then it *would* be a novel way of knowing. As I said. Arfa |
#11
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Mains off warning
"M.Joshi" wrote in message ... We occasionally find that the circuit breaker trips for a circuit in the kitchen and if left unnoticed, the food in the freezer could thaw out. Circuit breakers don't trip for no reason. Find the cause and fix it rather than resorting to a workaround, you'll be happier in the long run. In particular, put the fridge/freezer on its' own circuit breaker. The inrush current when the compressor starts is probably close to the circuit breaker's rating and anything else on the circuit would likely cause the breaker to trip. Also the more times the breaker trips, the less amperage it takes to trip it the next time. Breakers are de-rated over time, and an old appliance and an old circuit breaker are not a good combo. Dave |
#12
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Mains off warning
M.Joshi wrote in
: Hello, Does anyone know if there are any websites that have circuit diagrams for a mains warning alarm that sounds when the mains is off? We occasionally find that the circuit breaker trips for a circuit in the kitchen and if left unnoticed, the food in the freezer could thaw out. Thanks. Simple: Neon bulb connected to mains illuminates CDS cell or photodiode. Aformentioned light sensor biases trasnistor off, fixed trasnistor biases base on. Trasnistor controls beeper module. LV side powered by couple AA cells, as required for the beeper. Two: Small plugin trasnformer: Trickle charges rechargeable battery. Biases PNP trasnistor off, resistor to pull PNP trasnistor on. Trnasistor controls beeper, powered by rechargeable battery. |
#13
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Mains off warning
Extremely simple:
You need a small, normally-closed relay powered by the mains, or by a DC "wall wart" connected to the mains. Wire its normally-closed contacts to a battery and buzzer. Mains power keeps those contacts open and keeps the buzzer from sounding. |
#14
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Mains off warning
M.Joshi wrote in
: Hello, Does anyone know if there are any websites that have circuit diagrams for a mains warning alarm that sounds when the mains is off? We occasionally find that the circuit breaker trips for a circuit in the kitchen and if left unnoticed, the food in the freezer could thaw out. Thanks. A UPS (Uninterruptable Power Supply) like APC makes usually beeps when on battery. If you have an extra one (bad battery?) you could plug it in to the same outlet and let it chirp away when the breaker trips. Plug a clock in to it so some current is being used, and your problem is solved with all commercially available devices. :-) Puckdropper -- Wise is the man who attempts to answer his question before asking it. To email me directly, send a message to puckdropper (at) fastmail.fm |
#15
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Mains off warning
"mc" wrote in message ... Extremely simple: You need a small, normally-closed relay powered by the mains, or by a DC "wall wart" connected to the mains. Wire its normally-closed contacts to a battery and buzzer. Mains power keeps those contacts open and keeps the buzzer from sounding. I said that a few posts up ... ;-) Arfa |
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