AC motor voltage conversion?

"Morgans" wrote in message
...
|
| "John Ammeter" wrote in message
| ...
| Why does everyone think the voltage is 110/220??
|
| If that actually was the voltage you had in your house you'd be very
unhappy.
| The nominal voltage is 118/236 with a +/- 5% range so you can see
that 110/220
| is actually outside the acceptable range.
|
| Well, duh, John!
|
| Why is a car called a car?
|
| People (except you and a few others) don't really care what comes
squirting out
| of their wall plugs, and what to call it, as long as it makes things
work.
|
| It isn't 120/240 either. It is way too awkward to call it 118/236,
even though
| that is most accurate. Calling it 110/220 gets the idea across... Let
the
| electrical engineers and others that get hung up on exactly what it
is, figure
| out how to fight convention.
|
| To me, it's still 110/220.
|
| Now, let's get really weird, and figure out what comes out of the
plugs at my
| school. Three phase, split off to use single phase, now is it Delta
or Y? 95%
| of the people in the US don't know and don't care. What will they
call that
| 208?
| --
| Jim in NC
|

According to my fuzzy memory Delta is 208 and since there isn't a
neutral or center reference 110 is not available. Y configuration gives
you 220 from leg to leg while from each leg to the common center
(Neutral) gives you 110. From there you go to how the transformers are
configured, I.E. Delta/Delta or Delta/Wye or Wye/Delta. All of which I
do not remember how each effects the voltage result.

--
Jarhead



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It isn't 120/240 either. It is way too awkward to call it 118/236, even
though
that is most accurate. Calling it 110/220 gets the idea across... Let the
electrical engineers and others that get hung up on exactly what it is,
figure
out how to fight convention.

To me, it's still 110/220.

I call it that as well; but I have seen 125.

Now, let's get really weird, and figure out what comes out of the plugs at
my
school. Three phase, split off to use single phase, now is it Delta or Y?
95%
of the people in the US don't know and don't care. What will they call
that
208?

I would but that figure closer to 99.5%

I think that's unfortunate, since the easiest way to save money and energy
at the same time is to run motors on three phase power; and three phase Y is
the only place you'll ever see anything properly called 208 volts.

BTW, in my neck of the woods, if you were a major account, you used to get
only open delta unless you paid for the installation of closed delta--and it
was well worth the price!

Peter

John Ammeter wrote:
Why does everyone think the voltage is 110/220??

If that actually was the voltage you had in your house you'd be very
unhappy. The nominal voltage is 118/236 with a +/- 5% range so you can
see that 110/220 is actually outside the acceptable range.

John

actually in my travels, ive seen 90-140 volts nominal for the
"standard" 110V outlet. so it is a bit more than 5% tolerance

The service you describe is 120/208V. In the industry where I worked we
called it "Network"... 120/208 3 phase is only used in high density or
commercial areas where the utility has a need for 3 phase for elevators,
motors, etc. It's a Y configuration with 120 degrees between the phases.

Now, out in the hinterlands, the normal configuration is a 120/240 delta
setup. If you want 3 phase there it's a 3 phase delta.

In Seattle, most apartments are 120/208 and most private homes are
120/240, both single phase. A problem happens when a condo/apartment
dweller replaces his electric range with one he bought at a garage sale
or an appliance dealer that doesn't ask the right questions of the
buyer. What do you think happens when you operate a 240 volt device on
208 volts??

Now you know more than you ever wanted to know... amaze and confound
your friends with your newfound knowledge...

John

Morgans wrote:

"John Ammeter" wrote in message
...

Why does everyone think the voltage is 110/220??

If that actually was the voltage you had in your house you'd be very
unhappy. The nominal voltage is 118/236 with a +/- 5% range so you can
see that 110/220 is actually outside the acceptable range.


Well, duh, John!

Why is a car called a car?

People (except you and a few others) don't really care what comes
squirting out of their wall plugs, and what to call it, as long as it
makes things work.

It isn't 120/240 either. It is way too awkward to call it 118/236, even
though that is most accurate. Calling it 110/220 gets the idea
across... Let the electrical engineers and others that get hung up on
exactly what it is, figure out how to fight convention.

To me, it's still 110/220.

Now, let's get really weird, and figure out what comes out of the plugs
at my school. Three phase, split off to use single phase, now is it
Delta or Y? 95% of the people in the US don't know and don't care.
What will they call that 208?

Did you ever have your linemen wire up the tickler backwards?? That
gets real interesting when the voltage should be 240/480 open delta. I
had a job where they needed 3 phase for the elevator and only delta was
provided. Thank God it was a 120/240 system because when I wiggied the
voltage at the socket I found over 420 volts (I don't recall the exact
voltage) from one leg to the other. If it had been a 240/480 service
that would have been 840 volts... considered "high voltage" and
decidedly dangerous to the operator, namely ME.

I used that situation on a Test that I was writing for our Utility.
Strangely, only a few people got the question right. We hired a couple
of those fellows.

John

Peter Dohm wrote:
It isn't 120/240 either. It is way too awkward to call it 118/236, even

though

that is most accurate. Calling it 110/220 gets the idea across... Let the
electrical engineers and others that get hung up on exactly what it is,

figure

out how to fight convention.

To me, it's still 110/220.


I call it that as well; but I have seen 125.


Now, let's get really weird, and figure out what comes out of the plugs at

my

school. Three phase, split off to use single phase, now is it Delta or Y?

95%

of the people in the US don't know and don't care. What will they call

that

208?


I would but that figure closer to 99.5%

I think that's unfortunate, since the easiest way to save money and energy
at the same time is to run motors on three phase power; and three phase Y is
the only place you'll ever see anything properly called 208 volts.

BTW, in my neck of the woods, if you were a major account, you used to get
only open delta unless you paid for the installation of closed delta--and it
was well worth the price!

Peter

On Fri, 17 Nov 2006 19:08:34 -0800, John Ammeter
wrote:

Why does everyone think the voltage is 110/220??

If that actually was the voltage you had in your house you'd be very
unhappy. The nominal voltage is 118/236 with a +/- 5% range so you can
see that 110/220 is actually outside the acceptable range.

John


Officially here it is 115/230 and right now it's 119/238
Morgans wrote:

" wrote

Which is why they wire them for 220. It can be a lot.
If you can get 220v to the location, you will be a happy
camper.


I have such an air compressor, and it likes 220 the best. g

It starts quicker, and runs a little cooler, when running continuously.
It is possible to run it on a longer extension cord (made up for 220, of
course) without line loss being such an issue.

I have made up an assortment of pigtails to plug into dryer outlets, and
welder outlets. Yes, it is not protecting at the correct amps, but
monitored, it is not much of an issue, I think. A dead short will still
kick even a 50 amp breaker.

If yours is like mine, it pulls almost 15 amps running, and more at
start. It is necessary to have it's own circuit, if you want to run
much else with it on the same circuit.

My vote? Put up with the inconvenience (at times when you are using it
away from the shop) and run it on 220. It should last longer, and be
happier.

The wire configuration for both voltages should be pictured on the data
plate, or on the cover where the terminals are, that need to be changed.


--
Posted via a free Usenet account from http://www.teranews.com

On Fri, 17 Nov 2006 22:59:28 -0600, Andy Asberry
wrote:

On Fri, 17 Nov 2006 19:08:34 -0800, John Ammeter
wrote:

Why does everyone think the voltage is 110/220??

If that actually was the voltage you had in your house you'd be very
unhappy. The nominal voltage is 118/236 with a +/- 5% range so you can
see that 110/220 is actually outside the acceptable range.

John

I remember back in the fifties in vo-ag farm electrification class, it
was emphasized that you should make sure light bulbs were labeled for
120 volt. Perhaps prior to that they were rated 110 or 115? Maybe that
was the line voltage then. What is your take on it?

--Andy Asberry recommends NewsGuy--

Ontario rural electrification was 135 in the sixties. Urban bulbs
didn't last long if you were on a short line. This was done to make
sure there was a minimum 110 at the end of the line. Not every farm
had it's own transformer back then.

--
Posted via a free Usenet account from http://www.teranews.com

"John Ammeter" wrote

What do you think happens when you operate a 240 volt device on
208 volts??

Lower than rated HP produced, and shorter than normal motor life. Plus, when
you load the motor close to it's limits, the thermal protection or the breakers
kick off. A real pain in the arse.

For those that do not remember, I'm a carpentry teacher at a high school. I
have the 208 single phase power, and prior to me getting there, people bought
220 large power tools, instead of 208. It makes a big difference. I make sure
I order 208 equipment, and things are much happier.
--
Jim in NC

Did you ever have your linemen wire up the tickler backwards?? That
gets real interesting when the voltage should be 240/480 open delta. I
had a job where they needed 3 phase for the elevator and only delta was
provided. Thank God it was a 120/240 system because when I wiggied the
voltage at the socket I found over 420 volts (I don't recall the exact
voltage) from one leg to the other. If it had been a 240/480 service
that would have been 840 volts... considered "high voltage" and
decidedly dangerous to the operator, namely ME.

I was actually a radio and tv broadcast tech, and was lucky enough to never
encounter that problem. I say lucky enough because, although we had no
authorization to work on the main wiring of the buildings, there were
opportunities for errors inside our equipment--especially the transmitters.
We tried to be VERY carefull working in there; as the power supplies were
well into the thousands of volts DC, and both accidents and close calls had
occurred in the past.

The open-delta problem had been solved by my predecessor at my first
position as cheif operator, and had caused major reliability problems with
the transmitting equipment until a third transformer was added. He had also
organized a local society of engineers during that same period of time;
which may have been a related fact since the effect of a long run of
open-delta had to seem esoteric to the comptroller when he requested funds
to "purchase" the additional transformer--which would have been roughly
equal to the price of a new car.

Peter

In article ,
John Ammeter wrote:
Why does everyone think the voltage is 110/220??

Because that *is* what it 'used to be'.

If that actually was the voltage you had in your house you'd be very
unhappy. The nominal voltage is 118/236 with a +/- 5% range so you can
see that 110/220 is actually outside the acceptable range.

Over the years, the 'standard' has changed. *Several* times.

110V

115V

117V

120V

were _all_ the 'standard' over the years -- I have pieces of equipment
with all those voltages on the manufacturer's 'plate'.

In 'common'/casual usage, even when the 'standard' was 115V or 117V,
it was frequently referred to as "110V". In part because of 'mental
inertia' -- the standard had been 110V for a lot of years before the
'nominal' network voltage was raised to 115V. And it wasn't all that
many years before the 'standard' went to 117V, and then on to 120V.

Essentially, it is a 'class label', not an exact value.

There's even _more_ 'inertia' with regard to naming of the "2 hots, 180
degree out-of-phase" voltage level. It is *still* not infrequently
referred to as "220" even though the actual line voltage has been much
closer to 240 for 30+ years. A lot of people don't even recognize the
inconsistency of referring to '1 hot' as 120V, and '2 hot' as 220V.

The 'silliness' continues at the next higher voltage step. 'plates' on
gear will likely state (correctly) 480V, but calling it '440V' is still
_very_ common.

"commonly accepted wisdom" is that 110V, 115V, 117V, and 120V all
refer to the same thing, and similarly for 220V, 230V, and 240V.

It's similar to the "fact" that a "12 V battery" typically puts out 13.6V.