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My parents had good intentions, I guess, but the company that sold them this bad boy probably didn't. After blowing a fuse at their place, I noticed this box hooked up to the breaker panel. It was hooked up to a 50 amp breaker which led to the stove. I removed it shortly after I explained that there is no magic box to cut power bills, and they received a full chargeback through their credit card company when the installer of this device didn't even dispute that it was a scam. Not to mention, the way it was tied into the panel was not even close to being up to code - 2 wires into one breaker, one was stranded. They also charged just under a hundred bucks to wrap our hot water tank in bubble wrap. Sigh. The total was somewhere near $1500. I feel terrible for the folks who bought this and didn't know any better.

Anyways, that doesn't stop the curiosity. Obviously nothing useful, but what could this thing have possibly done? I think I see diodes, caps and resistors.. so I'm thinking maybe there's a transformer in that cylinder and maybe this is a power supply for the light on the box? Or maybe that's not an LED and none of this stuff does anything at all. I'm a little scared to open up the large cylinder. If you guys give me the go-ahead, I'll cut that open too. The company was called SolarTEK, and no, they don't do solar. Gotta hand it to them though, pretty decent production quality.

EDIT: Below it was suggested that this could be a power factor correction unit. Regardless of the usefulness of that at all in this context, this makes me wonder:

  1. Would such a device have functioned, being hooked up to only one circuit in the breaker?

  2. I saw an image while researching these capacitors that suggests on physical expansion of the capacitor, it breaks a fuse. Is that a type of surge protection? What would it take to trigger that? And if so, with this literally hooked up in-line with a stove, that couldn't possibly have protected the entire house from an actual surge, could it?

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kavisiegel
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    It's probably meant to be a power factor correction unit with the cylinder being a capacitor. I thought there was already a good answer here explaining why they're a waste of time but I can't find it at the moment. – PeterJ Dec 29 '14 at 09:29
  • Related: [Why do power companies never bother residential customers about power factors?](http://electronics.stackexchange.com/questions/85291/why-do-power-companies-never-bother-residential-customers-about-power-factors) – Ignacio Vazquez-Abrams Dec 29 '14 at 09:33
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    Also, hot water tanks are usually insulated enough. Worry more about the pipes (and don't bother paying someone else to do it, get pipe insulation sleeves and some electrical tape and handle it yourself). – Ignacio Vazquez-Abrams Dec 29 '14 at 09:35
  • @IgnacioVazquez-Abrams - That's pretty much what I explained to them as well. The company was pretty much out to get older folks by selling them what looks like efficient piece of mind. Anyways, thank you for the link. I'll be reading up on power factors this morning. I've edited 2 questions in above as well. – kavisiegel Dec 29 '14 at 09:42
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    I don't think the small silver pipes are diodes. I know these housings with the epoxy tip from thermal fuses. If the _ambient_ temperature is too high, they blow up. Here's a link, the datasheet nicely explains how they work: http://www.newark.com/67C6644 – sweber Dec 29 '14 at 09:55
  • Related: scam warning [If the energy meter sees a reactive load will it register a lower reading?](http://electronics.stackexchange.com/questions/19102/if-the-energy-meter-sees-a-reactive-load-will-it-register-a-lower-reading/19118#19118) – wbeaty Dec 29 '14 at 21:46

1 Answers1

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The red disks are MOVs (metal oxide varistors); these are the "surge protection" aspect of the device. There are four groups of them, for line-to-neutral and line-to-ground for both lines.

The small silver tubes are fuses that are intended to blow in order to prevent a fire when the MOVs fail, since they often fail shorted.

The large silver cylinder is a multi-section electrolytic capacitor, which is connected line-to-line. It is either a nonpolarized device, or the multiple polarized sections have been connected in such a way as to effectively make it nonpolarized. It is notionally there for "power factor correction", but this a waste of effort in a domestic application.

It looks like the big capacitor is also being used to drop the voltage (limit the current) to the indicator lamp, which is probably neon.

Dave Tweed
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