There is also, I believe, a difference in construction techniques. The US has a lot more wood structures, where Europe far more stone/masonry.
None. It seems both systems work and the inertia is humungous. Perhaps it would make more sense for my built-in convection microwave to run off 240, but it ain't that way.
Do you just have a center tap grouned isolation transformer? (I don't understand what you mean by 60/60 two phase.)
Since most built-in microwave ovens already have a dedicated 120 volt circuit, it wouldn't be too hard to convert it to 240 volts. And if manufacturers started to make 240 volt models, converting the circuit would actually be cheaper and easier than installing the microwave itself.
Robert
(I don't understand what you mean by 60/60 two phase.)
Yes. The center tap goes to ground and the two (out of phase) end taps go to hot and neutral on my outlets, for 120VAC to whatever is plugged in, and with hot and neutral both at 60VAC but 180 degrees out of phase with each other.
This scheme is popular in recording studios.
A number of the drives I've worked with were. DriCo 2.4 and 4.8Mb (one fixed, one exchangable disk) drives had to be put in the 19" cabinet with a fork lift truck. The CDC Lark 8Mb and
24Mb(?) drives were liftable by one person, but two made it much easier when it came to aligning it with the rails in a 19" rack.As for Media alone, some of our smaller framed female operators had to struggle with the CDC 300Mb exchangable packs (14" 10 platter jobs which went into washing machine-like drives). I still have a head- alignment (CE) pack for one of these sitting on the shelf above my desk, although about 12 of the 20 surfaces are head-crashed ;-)
This certainly isn't true of the UK, where it's become pretty impossible to get an electrician now, certainly one which will do a good quality job, and I would say most home electrical work is DIY. We have big "home" stores which sell everything required if you want to rewire your house, including Consumer Units (panelboards). Doing your own electrical work has always been popular, but doing pretty well all aspects of building/construction has become even more popular in the UK over last
10 years.I can't speak for the rest of Europe, but I've seen similar available in France. However, I think tradesmen are still easier to get in France.
Gfretwell didn't write that. I did.
Sorry for being unclear. It was the drive that was too heavy to lift, not the removable disk pack.
At least the 3340 and 3330 before it, didn't leak oil on the floor. 2314s were so bad they just incorporated a spare in the array. Buy 8, get 9.
However an insulation sufficient to block 5000 volts would be substancial. And God help you if your dog chews through a lamp cord.
Tim
| However an insulation sufficient to block 5000 volts would be substancial. | And God help you if your dog chews through a lamp cord.
You'd definitely need help scraping the mess off the walls :-)
There are definitely some cases where lower voltage is better. Consider a light bulb suitable for ever higher voltages. A 100 watt filament for
5000v would be thinner and/or longer than a 4 watt filament for 120v.I do think a higher voltage is more suited to larger appliances in a home. Incandescent lighting and some smaller devices would be better at a lower voltage. I have posted before about the system design I would have made if I had the opportunity to do so without legacy economic impact (e.g. if I could go back via a time machine and make the early system design decision). The system I would have would be a dual-voltage system in the home. Larger loads would always be connected line-to-line at 288 volts. That would be
144 volts relative to ground on single phase supplies, or 166 volts relative to ground on three phase supplies. This might even be made higher such as 360 volts (180 or 208 volts to ground). The lower voltage would always be single phase with 12 volts relative to ground (but might be set up as dual phased with 12-0-12 for 24 volts line-to-line). This would primarily be used for incandescent lights up to 60 watts, electric shavers, small tools, and small appliance wall-warts. Larger appliances would use the 288 volt system. The service drop would be 288 volts, and the 12 or 12/24 system would be derived from it.So with the above system, would you find 288 volts, or maybe even 360 volts, acceptable?
Well, what all books say, is, that the voltage is stepped up from the alternator at the power plant (usually ~21 kV for ~300 MW units)to several hundreds of kV (usually 150 kV,220 kV and 400 kV)to make transmission of large amounts of power more efficient then stepped down at 15kV for primary distribution, then stepped down at 400/230 volt for secondary distribution (at least on this side of the pond).This is, I think, as efficient it can be, from the very start.(Each stage has efficiency close to 99%).The final domestic voltage (low voltage,LV)is selected for safety mostly...Here, in EU, you can have in your home 3-phase to drive large A/Cs or whatever, and the same type of distribution is used for industrial areas...Large hotels/industries or whatever are supplied directly from 15kV and do their own transforming, and even larger (half a dozen for all of Greece)are supplied from 150 kV.Of course, the hotel load of, say, a brown coal power station, consists of ~two dozen 1MW 6.6kV (6600 volt motors).Even at that voltage the motors draw like, 150 A each phase.That voltage of course, is extremely dangerous, and when someone is working on such a motor, they take the whole circuit breaker out of its bus bars, on a trolley like a supermarket (trolley), so that no one turns the motor on.Even if you don't touch the contacts and the motor is energized, imagine being pulled by a shaft of a 1500 HP motor...
-- Tzortzakakis Dimitrios major in electrical engineering mechanized infantry reservist dimtzort AT otenet DOT gr
Yes, I agree Phil. I was trying ti imagine an entire residential system at elevated voltages. And boy, I could sure put good use to that time machine if you ever find it! Make wine today, push a button and instant aged! drink it, then go back. Wat-a-plan!
Tim Gard
Unless you have a super energy hog of a home (e.g.: resistance heating or electrically powered demand water heater) a 200 amp service is "Plenty". The reality is that most familys would not see any difference to their life styles had they only a 100 amp service.
I definitely would like to see more 240 volt appliances to include dish washing machines and "super" microwave ovens. But 120/240 is "pretty good."
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| Unless you have a super energy hog of a home (e.g.: resistance heating or | electrically powered demand water heater) a 200 amp service is "Plenty". | The reality is that most familys would not see any difference to their life | styles had they only a 100 amp service. | | I definitely would like to see more 240 volt appliances to include dish | washing machines and "super" microwave ovens. But 120/240 is "pretty | good."
I have seen microwave ovens that use 240 volt. But they were big ones, probably with a lot of power. I'd like to see more appliances available in 240 volt (6-15P or more as the case may need to be) versions. One thing that will need to be changed for that is removal of NEC 210.6(A)(2).
My big beef is against anything that needs a 3-wire supply (dual voltage). But, I do read from computer power supply specs that most of them are more efficient on a 220-240 volt power source (though not enough so to justify using a step-up transformer to get it).
What, pray, does it say?
Exactly.
"Standard" US electric clothes dryers have 240 heaters but 120 volt motors and timers/electronics. Electric stoves have 240 heaters but 120 volt timers/electronics. That might have something to do with the fact that in a significant part of the market (condos, in particular) you don't get 240 volts but only 208. Running a 240 volt motor on 208 is asking for trouble. Running a 240 heater at 208 doesn't make much difference and in any case it isn't a "big deal" to substitute a 208 volt heater.
In alt.engineering.electrical John Gilmer wrote: | | |>
|> I have seen microwave ovens that use 240 volt. But they were big ones, |> probably with a lot of power. I'd like to see more appliances available |> in 240 volt (6-15P or more as the case may need to be) versions. One |> thing that will need to be changed for that is removal of NEC 210.6(A)(2). | | What, pray, does it say?
You couldn't look it up?
Basically it says that circuits cannot be wired to supply voltage in excess of 120 volts between conductors for loads less than 1440 VA. That means for smaller appliances, we're stuck with 120V only, unless we try to get clever and insist that our 2000W 240V 6-15P welder is portable enough to use in every room of the house :-)
|> My big beef is against anything that needs a 3-wire supply (dual voltage). | | Exactly. | | "Standard" US electric clothes dryers have 240 heaters but 120 volt motors | and timers/electronics. Electric stoves have 240 heaters but 120 volt | timers/electronics. That might have something to do with the fact that in | a significant part of the market (condos, in particular) you don't get 240 | volts but only 208. Running a 240 volt motor on 208 is asking for trouble. | Running a 240 heater at 208 doesn't make much difference and in any case it | isn't a "big deal" to substitute a 208 volt heater.
OTOH, if all of the load is well balanced over the 2 line conductors, that should be more efficient even for the same load.
Europe has proof that the electronics can run on 240 volts. So can motors (but 208 volt versions would be needed). So can light bulbs safely if they are of the bi-pin type (though at the small wattages, a low voltage from a tiny transformer might be better).
A true two-wire applicance could still be shipped with a 14-XXP cord, but you could substitute a 6-XXP for it (I would).
Ever seen a 14-15R receptacle. Try plugging a 6-15P into it. It fits!
Australia has been 240VAC only for domestic use since before I was born. I'm really glad we don't have to screw around with multiple voltages in homes.
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