PeterD wrote:

Except for the fact that the NA standard is 120/240 volts (there are a
number of authorative references, feel free to Google them). So your
two 'phases' are almost dead on (probably measurement error) and the
240 is slightly low (measurement error, seems odd that it can be off
consdiering that it is supposed to be the sum of the two 120 legs.)


Not at all. He measured them at diffent times, unless he has three
meters.


--
You can't have a sense of humor, if you have no sense!

stan wrote:

Was going to ask someone knowledgeable to post the percentage voltage
variation allowed in the USA (or wherever it is) for 'normal service'.
Average values of +5 to -10% of the nominal, in California, as
delivered at the service entrance,

jk

"RoyJ" wrote in message
...


Assuming a nominal 240VAC supply, 245V is in no way "not correct" -- it's
only about a 2% overvoltage.

And since there is likely no load in shop when the install was taking
place, the 245 would be a higher than normal reading.

But I question the use of "3phase" and "245 volts" in the OP question.
Around here, 245 volts would be perfectly normal for a single phase
circuit, very high for a "standard" 208/3 phase delta.

208 three phase isn't delta. It's wye.

Harold

On Fri, 17 Jul 2009 22:50:07 -0700, jk wrote:

PeterD wrote:

It was determined that it
would be necessary to standardize all voltages (just not the low
voltages we are discussing here) to allow interconnection, and direct
substitution of equipment.


Not much standardization at voltage over 600V, at all.

13.8, 12.47, 12.00 KV are all fairly common MV distribution voltages
around here.
jk

It seems that way to you. More study can reveal how those
distribution voltages are related. You may bother or not.

PeterD wrote:

It was determined that it
would be necessary to standardize all voltages (just not the low
voltages we are discussing here) to allow interconnection, and direct
substitution of equipment.


Not much standardization at voltage over 600V, at all.

13.8, 12.47, 12.00 KV are all fairly common MV distribution voltages
around here.
jk

On Mon, 06 Jul 2009 06:16:42 -0700, Archimedes' Lever
wrote:

On Mon, 06 Jul 2009 03:48:34 -0700, Gunner Asch
wrote:

Hummm perhaps you havent any idea that Im one of the cheapest
CNC service techs in So. Cal?

Bwuahahahahaha! I'll bet your skill set matches your price schedule.
Low and lame.

Hummm? Yeah, you'd probably be better at that.

So hire me and find out for yourself.


"Lenin called them "useful idiots," those people living in
liberal democracies who by giving moral and material support
to a totalitarian ideology in effect were braiding the rope that
would hang them. Why people who enjoyed freedom and prosperity worked
passionately to destroy both is a fascinating question, one still with us
today. Now the useful idiots can be found in the chorus of appeasement,
reflexive anti-Americanism, and sentimental idealism trying to inhibit
the necessary responses to another freedom-hating ideology, radical Islam"

Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno

On Jul 5, 1:40*am, John E. wrote:
I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

Thanks.
--
John English

Are we sure that the electrician was given
the option or assignment to do a needs
analysis?

Do we know that he wasn't given specs to
meet before the machines were in place?

If he was asked to meet specs from a plan,
is he really on the hook for the full needs analysis?

"Greegor" wrote in message
...
On Jul 5, 1:40 am, John E. wrote:
I have been asked to offer an opinion in a sensitive situation.

"Are we sure that the electrician was given
the option or assignment to do a needs
analysis?

Do we know that he wasn't given specs to
meet before the machines were in place?

If he was asked to meet specs from a plan,
is he really on the hook for the full needs analysis?"

It really isn't known if that actually caused the failure. If the equipment
was new, there would have been instructions and customer support including
things to look out for. What exactly failed? Capacitors can self-destruct
without warning, a rectifier can short. How can we tell which came first?
The equipment is used so there can be no guarantee. I bet you don't have
measurements of the actual voltage at the time of installation. This has
been a problem lately with a bank of 10 year old audio amps that have been
self destructing with blown caps and charred power supplies. No indication
of why.

Another controversy revolves around how thorough can an installation be
before a customer goes to a lower bidder. Even landing men on the moon had
elements of uncertainty.

But I would have measured the primary voltage if it were present. Lacking
an installation manual, I would have at least looked for taps.

You can rent a chart recorder to see what the line voltage is doing over the
course of a month. It may be a building management or electric company
issue like a poor or missing neutral. It makes no sense to me that a 20%
overvolt would have done any damage unless the equipment was on it's last
legs.

wrote:



13.8, 12.47, 12.00 KV are all fairly common MV distribution voltages
around here.
jk

It seems that way to you. More study can reveal how those
distribution voltages are related. You may bother or not.

I know exactly how they are related, (I some how doubt that you do
given the phrasing in your post) and I know exactly who provides what,
and why, but that in NO way makes them 'standardized'.
"You may believe that or not", it matters nothing.

jk

On Sun, 19 Jul 2009 11:24:31 -0700, jk wrote:

wrote:



13.8, 12.47, 12.00 KV are all fairly common MV distribution voltages
around here.
jk

It seems that way to you. More study can reveal how those
distribution voltages are related. You may bother or not.

I know exactly how they are related, (I some how doubt that you do
given the phrasing in your post) and I know exactly who provides what,
and why, but that in NO way makes them 'standardized'.
"You may believe that or not", it matters nothing.

jk

Your arrogance does not impress me. I have some understanding of
transformers as well. And i do not care if i impress you. Bring
electronics instead of insults.

wrote:


I know exactly how they are related, (I some how doubt that you do
given the phrasing in your post) and I know exactly who provides what,
and why, but that in NO way makes them 'standardized'.
"You may believe that or not", it matters nothing.

jk


Your arrogance does not impress me.

Having knowledge is arrogance?

I have some understanding of
transformers as well.

SO ???? What does that have to do with standardization of MV
distribution voltage(s) NADA

And i do not care if i impress you.
WHy should I care? Nor did I ask you to impress me, did I?

Bring
electronics instead of insults.
And electronics being relevant not at all to MV distribution, why
would I?

And you see an insult in my doubting your unsupported claim of
knowledge? One without the barest hint of support?
A little thin skinned is it not?

jk

GO DEEP SIX YOURSELF ARCHIMITURD
WATCH AND SEE IT'LL DO WONDERS FOR THE GROUP

I AM PROTEUS

On Jul 5, 2:40*am, John E. wrote:
I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

Thanks.
--
John English



TWO WORDS

LOS ALAMOS



I AM PROTEUS

On Jul 31, 6:01*am, Proteus IIV wrote:
On Jul 5, 2:40*am, John E. wrote:





I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

Thanks.
--
John English

TWO WORDS

LOS ALAMOS

I AM PROTEUS