Mexican electrical issues

Mexico's 'official' voltage is 127V.

So yes it causes trouble. A bucking transformer or two might help you.

Graham

A friend of mine worked for the local water authority many years ago, and he had a similar problem at a remote pumping station, where light bulbs and pump motors would fail in short order. Turned out that there was an intermittent neutral connection at the pole transformer half a field away, which was allowing the line voltage to come up to the three phase level intermittently - over here that's up to 415v from 240v. I've probably explained that wrong, I'm not an electricity distribution expert, but the gist of it in terms of levels and the cause is right, so I'm sure someone who is au fait with the subject can pick it up and know what I'm trying to say.

Arfa

Yup, I know exactly the scenario you mean.

In the USA a similar thing can happen with their ( I'm the UK too btw ) 'centre-tapped' 2 phase 240V too. The 120V single phase supply can go soaring.

Graham

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But with that fault, for the UK does not that just mean the same usable supply stays at 240V but instead of neutral being a nominal near ground it goes up 150 V or whatever, which should not blow equipment. Isn't it more a problem of very low loading or heavy inductive loading / unbalanced loading that shifts the supply up in voltage range to dreate surge/oversupply to equipment problems.

The voltage can fluctuate according to the appliances connected within each property/dwelling supplied from that transformer. I posted an explanation of this a little while ago.

As I said, I'm no expert on electricity distribution, but this problem causing the voltage to shoot up to interphase level was something to do with the PME overhead distribution system that is still around in some UK rural areas, and was the system that this pumping station was fed from. Although it was a long time ago, I can quite clearly remember him installing a voltage recorder in the station, which gave the clue to what was happening. He then met the supply company lineman on site, and that guy pinned it to an intermittent neutral connection at the transformer. It just seemed to me that this sounded like just the sort of thing that the OP was describing, and given that he said the wiring looked pretty dodgy to him, and much of the North American continent is fed via overhead pole transformer systems, I thought that it was an idea worth considering.

Arfa

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Here is witnessed similar surge, urban setting. Someone , non technical, I know, retuned from abroad about 3 or 4 in the morning. Sitting down unwinding, with the lights on, he noticed the room light was getting noticeably brighter and brighter over 10 seconds or so until it popped , quickly followed by a sidelight. Next day he discovered VCR blown and a couple of other items blown. Could he get compensation from the utility - no? How would you get a slow increase with that transformer fault condition, intermittant or instantaneous but not gradual increase.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

I'm joing this late, but here's some more practical suggestions:

1. Buy a REAL surge protector such as a Trip Lite ISOBAR. Around 0. There are clones made by someone else for Hi-Fi's for about 0, IMHO not any different except in marketing.

1. Buy one from Trans-Tector. A lot more money, but they make them for use in air traffic control centers, hospitals, etc where you can't turn off or unplug equipment during a lightening storm.

2. Make one out of a small (rating) fast blow fuse and a 150 volt MOV. When you get a big surge, the MOV fails, which causes it to short and the fuse blows. Possible put this in front of the surge protector,

1. Buy a commercial grade UPS.

Geoff.

Surges are very unlikely to be the problem.

More likely is long term modest overvoltage.

Graham

Exactly how modest? When I lived in the U.S. (Philly, until 1996), the line voltage was always 127 volts. If you figure a range of 10% is ok, than that would be 133 volts as the top limit for a 120 volt device.

More likely it's 15% which would take it up to 138 volts.

That's why Israel chose 230 volts, people could bring applicances from Europe and the rest of the world that was 220, or the U.K., where it was 240 volts and they generaly would work ok. The E.U. (which AFAIK includes the U.K.) has switched to 230 volts as part of their "normalization program".

My expectations are that the cheap appliances are burning out because they are cheap appliances. Things are not built like they used to be.

For example, if he wants to get them a mixer, either buy them a Sunbeam at a garage sale, or a new Kenwood if he can get one. I bought one here (in 230 volts) because after a lot of research I found that they were far more relaiable and better made than the current Kitchen Aid ones.

For example, my mixer, which is a mid range model, is 1000w 2-3 times the power of anything Kitchen Aid sells.

Geoff.

snipped-for-privacy@mendelson.com (Geoffrey S. Mendelson) wrote in news: snipped-for-privacy@cable.mendelson.com:

Trip Lite Isobar surge protectors come in several models, some including protection for phone line, coax cable, etc.

Although their list prices are high, street prices are surprisingly affordable, $43 and up.

Loose neutral, probably within his own home, not the power company's problem.

A surge protector won't do anything to prevent damage from high line voltage, the voltage has to get *really* high before they even kick in, like 400-600V. A constant voltage (ferro-resonant) transformer would do the trick but those are big, heavy, inneficient, and therefor run hot and tend to hum as well.