280V motor on 230V circuit

charles wrote:


I always thought the British pound was a unit of currency. :)
Anthony
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cleverly, we use the same word for two different things to confuse foreigners.
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From KT24 - in "Leafy Surrey"

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Just wait until you run into BTU's....
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In alt.engineering.electrical Anthony Matonak
| charles wrote:
|>>> It is necessary to distinguish between mass and force but they are both |>>> measured in pounds in the english system. |> |>> The "English" system uses the "stone" as the measurement of mass. |>> The pound ('lb') is the unit of *FORCE*. |> |> The 'Stone' is a unit of mass, not "The unit of mass" |> |> All the engineering I ever learned in the British (Imperial) system used |> pounds. | | I always thought the British pound was a unit of currency. :)
That's why I never wanted to carry around the British currency. It can be quite a chore to carry 50 pounds in your pocket :-)
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snipped-for-privacy@ipal.net wrote:

Well, if it's true that "A pint's a pound the world around" then you don't need to carry it all in your pocket. :-D
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Morris Dovey
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that saying must be some years old.
A pint's now about three pounds ;-(
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Also a US pint (16 fl.oz) is smaller than an Imperial pint (20 fl.oz), so that would make beer more expensive in the US ;-)
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Andrew Gabriel
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snipped-for-privacy@charleshope.demon.co.uk says...

It is *the* unit of mass. The pound-mass is a recent abortion.

You must be a kid.

Only if you spell funny.
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Keith

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No - 68!!!

Even in 1961 the MKS system was the norm.
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snipped-for-privacy@charleshope.demon.co.uk says...

I first heard pound-mass about ten years ago. All through high school and college the English unit for mass was the stone (as in the FSF system of measurements).

Sure, but you still spell like a frog. ;-)
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krw wrote:

Is the unit for "Are you getting any lately?", still furlongs per fortnight?
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If you call the past 100 years or so, 'recent'. I myself have text-books from the '50's that use this 'recent abortion' as you call it.
Considering the separation of force and mass was first worked out *after* the original 'pound' for weight was in common use, it was necessary to separate which 'kind' of 'pound' was being talked about. The one that represents how much *force* is being applied to something, or the one that describes how much resistance to acceleration something has.
But for a long time a 'pound' of something was a certain amount of mass -or- the force applied to a surface by placing that certain amount of mass on it (such as used in 'dead-weight' testers for pressure instruments).
In a few obscure bits of engineering, you can even find the term 'kilograms of force' used. Obviously that is the force applied by placing a kilogram of mass on top of something. You can even find some pressure gauges calibrated to read 'kg/cm^2'. Proof that you can mess up things even with the metric system. ;-)
I'm not sure how old the 'stone' is, but I suspect it too was around before we knew the difference between force and mass. Stone is common in UK still, but it never caught on in the colonies, even as far back as colonial days when 'hundredweight' and 'long ton' were in common usage.
Trouble with pound-mass (lbm) and pound-force (lbf) is that to make F=MA work out, you need to keep another 'conversion factor', the dreaded g-sub-c (g-sub-c = 32.2 lbm-ft / lbf-s^2), around and figure out when to throw that into the mix.
daestrom
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:)
Really gets to be fun when working with things like foot-pounds, as in torque, angular momentum, and the pressure due to a certain depth of water. Trying to remember when the pounds are mass and when they are force gets to be fun.
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bz 73 de N5BZ k

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In the early '50's there were two other units around- the poundal (1/g pounds force) or a mass called a slug (g pounds mass). Learning mechanics with these units (don't use them together)is worse than working in the stone, furlong, fortnight set of units. The poundal was introduced in 1879 as part of the "english set of units" (Wikipedia is sometimes useful).
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I certainly remember the poundal.
The various old english measures: chain, rod, quarter, peck, etc, were, of course, very useful to teach children arithmetic since they all came with different bases.
and of course you can measure viscosity in Acres per year - if you want to.
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You forgot the poles and perches, the bushels, and of course, the LSD.
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daestrom wrote:

An excellent compilation of measurement units, may be found here:
http://www.unc.edu/~rowlett/units/index.html
Note that mass, (kilogram), is the only fundamental unit that is not defined by a property of nature.
--
Virg Wall, P.E.

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http://www.engineeringtoolbox.com/mass-weight-d_589.html
I don't think any of them are 'too complicated'. It is easy enough to convert from one to another.
However, FAILURE to convert has been known to cause problems, such as a Mars mission that crashed because the wrong units were used.
http://www.cnn.com/TECH/space/9909/30/mars.metric /
--
bz

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Yes, because as the germans say-"Sie nehmen Strom direct aus der Leitung"-They draw power directly from the wire. So it's a higher impulse current than any on board diesel can provide;_)

Of course you are, but I thought there might be other members of the group, that don't. I didn't know until I read the article. The large, 15,000 HP, 11 MW diesels we have here at our local power station, have a final steam stage, for better efficiency. The URL of our local college, where I got my degree, is www.teiher.gr , but I'm not sure if they got an english version.

In Germany, they have special locomotives for freight trains, and special for passenger ones. The former desingned for larger traction power, the latter for higher speed. I have more experience with ships, since there are no railroads in Crete, but there's a lot of sea, and islands in Greece:-) I'll never forget my trip to Rhodes, where my batallion was situated, by rail from Korinthos (the infamous boot camp) and with ship to Rhodes. She was full of soldiers and commuters:-) NB.:There are railroads in continental Greece.
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Tzortzakakis Dimitrios
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----------------------------
writes:

-------- Yes -you are shorting a part of the winding but the switching is a bit more complex than that so that short circuit currents are limited to reasonable values. It is a multistep operation with reactor switching. On-load tap changers are expensive and are generally limited to applications where this is absolutely needed (I have seen one where the tap changer was nearly as large as the transformer). --------------

------------- Possibly but probably not- I am out of date on this but I would expect that the old way of good switches plus reactors might still be the better way. It saves a lot of control wiring plus a lot of money to operate thyristors at 300KV and 500A or more and I doubt whether they would be cost effective or technically advantageous otherwise. --------------------------

"on load tap changers"? Not likely. These were applied to transformers only where it was worth the effort. Definitely transformers in rural areas- typical pole pigs- would have to be de-energized as the tap changer is a manually operated switch inside the tank. Some larger transformers did have off-load but live changers operated from ground level. What you saw could have been somethng else altogether. Delta primaries as you indicate were around when you were a kid, would, in most areas mean that you are now a pensioner. I remember cases of conversion from delta to star for distribution primaries in small towns being done about 60 years ago and use of delta for transmission died much before that.
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