Ï Ýãñáøå óôï ìÞíõìá
...
In alt.engineering.electrical Michael Kennedy
wrote:
|
| wrote in message
| ...
| In alt.engineering.electrical operator jay wrote:
| |
| | "You" wrote in message
| | ...
| | In article ,
| |
| | wrote:
| |
| | There are two different flavors of 220/230/240 volts. Some places
| | have a
| | simple system with one wire hot and one wire grounded. Other
| | places have
| | a split system where the voltage is split in half to get
| | 110/115/120 volts
| | relative to ground, by adding a additional "middle" conductor that
| | is the
| | grounded one.
| |
| | Sonny, you need to LEARN the difference between Ground and
| | Neutral......
| | before you spout any further BS.......
| |
| | What he wrote looks reasonable to me in terms of ground and neutral.
| | Neutral is the grounded conductor where I live. He does not say to
| | use a ground as a neutral, if that's what you're getting at. I can
| | only guess that that may be what you're getting at, you haven't
really
| | said.
|
| He might be one of those "knows just enough to be really dangerous"
people
| on the net. I didn't even mention "neutral". My intent was to explain
it
| in a simpler way for someone to just understand the basic difference.
The
| term "middle" was to convey a little more information than "neutral"
would
| SNIP
|
| Well, I understood what he meant, but maybe I took it the wrong way.
When he
| said middle conudctor I was thinking the center lug on the transformer
which
| is grounded and used as the neutral.

That is what I meant when I said middle conductor. I intentionally
avoided
calling it neutral for the person I was responding to. I did quote it to
make it clear (but this apparently was not clear enough for at least one
person) for others that I was using some other term.

--
Nope. LV (low voltage)230-V in Europe is just sufficient for 1 km distance.
MV (medium voltage) 20 kV for 60 km. HV (high voltage) 150 kV for 220 km.
EHV 400kV for 500 km with stability issues. 110 volt is so low you need a
transformer outside each building....



--
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
hordad AT otenet DOT gr

--
Nope. LV (low voltage)230-V in Europe is just sufficient for 1 km
distance. MV (medium voltage) 20 kV for 60 km. HV (high voltage) 150 kV
for 220 km. EHV 400kV for 500 km with stability issues. 110 volt is so low
you need a transformer outside each building....



--
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
hordad AT otenet DOT gr



Learn the system before you criticize it.

It's not 110V, it's 240V, we simply split it with a grounded center tap
which gives 120V between each side and neutral, or 240V between the sides..
There's no transformer per house, except rural applications. Generally 5-10
houses are on each transformer, sometimes more. The problem with long runs
is that the voltage fluctuates substantially with large loads such as
central air conditioning. Standard North American residential service is 200
Amps 240V, I gather this is quite a bit larger than typical European
domestic stuff, so stretching it over 1km distance would require
prohibitively large cables or suffer from wide voltage swings. Makes more
sense to run 7200V down the street and locate a smallish transformer near
every half dozen houses.

jakdedert wrote:

Jamie wrote:
hr(bob) wrote:

On Apr 26, 6:14 pm, Jamie
t wrote:

Deodiaus wrote:

I have a broken pool motor [magnetek y56y] which will cost a bundle to
fix
or repair.
While doing a search on the web, I found the same model (really cheap)
but
wired for 280V, instead of the 230 V load that my wiring is supplies.
Now, I was thinking of buying the cheap 280V model and installing it
instead. Aside from rotating at a different speed and
maybe some power inefficiencies, are there any other drawbacks of
using the 280V model
instead?

are you sure it isn't 208 ?

--http://webpages.charter.net/jamie_5"


I'd be suspicious that the 280V was a misreading somehow of 230V.
that sounds more plausible.

I'm a little confused about a 230 volt circuit. In what part of the
world does the utility supply 230v?

Most countries are 230 Volts (50 Hz) with some exceptions, such as North
America, parts of South America, Japan, and a few others. Nearly all of Europe
is standardized on 230 Volts 50 Hz, although outlet/plug shapes still vary from
country to country.

Ï "James Sweet" Ýãñáøå óôï ìÞíõìá
news:WMGTj.5083$ch1.2983@trndny09...


--
Nope. LV (low voltage)230-V in Europe is just sufficient for 1 km
distance. MV (medium voltage) 20 kV for 60 km. HV (high voltage) 150 kV
for 220 km. EHV 400kV for 500 km with stability issues. 110 volt is so
low you need a transformer outside each building....



--
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
hordad AT otenet DOT gr



Learn the system before you criticize it.

It's not 110V, it's 240V, we simply split it with a grounded center tap
which gives 120V between each side and neutral, or 240V between the sides.
I'm perfectly aware of this, only in theory, though, as I've never been in
USA. I have worked, though in the decommisioned US base in Gournes, really
impressive your distribution systems:-)
And in Europe we have 400 V (3 phase) line to line voltage. It's 230 line to
earth. Large motors and conditioners use 3 phase. Normal residence is 40 A
230 V single phase, or for energy hogs 400 V 3 X 40 A 3 phase..
There's no transformer per house, except rural applications. Generally
5-10 houses are on each transformer, sometimes more. The problem with long
runs is that the voltage fluctuates substantially with large loads such as
central air conditioning. Standard North American residential service is
200 Amps 240V, I gather this is quite a bit larger than typical European
domestic stuff, so stretching it over 1km distance would require
prohibitively large cables or suffer from wide voltage swings. Makes more
sense to run 7200V down the street and locate a smallish transformer near
every half dozen houses.

Europe.

I also noticed just last week that Malaysia and Singapore use 230V (@50Hz).

Residential power in Sweden is 400V 3 phase, main fuses normally 25A
or lower.

Room outlets are wired with one phase, neutral and ground to get 230V.

There is a smallish transformer station in the neighborhood which
probably powers two entire blocks. I would guess somewhere around 20-30
houses.

? "Thomas Tornblom" ?????? ??? ??????
...
Residential power in Sweden is 400V 3 phase, main fuses normally 25A
or lower.

Room outlets are wired with one phase, neutral and ground to get 230V.

There is a smallish transformer station in the neighborhood which
probably powers two entire blocks. I would guess somewhere around 20-30
houses.
Absolutely the same here, in Greece we are using only Schuko sockets, from
german Schutzkontakt, security contact. There is a larger substation, maybe
2-3 for a city (in Iraklion we have 3, 180,000 residents) that steps down
from the transmission voltage, 150 kV down to primary distribution voltage,
15 kV that is the distributed with cables buried in earth. Our local power
station has units with 15 kV (older) and newer with 6.6 kV alternators, all
is stepped up to 150 kV even for the ~15 km to Iraklion. In capitals, like
Athens, electricity comes at 400 kV, is stepped down to 150 kV for secondary
transmission, again goes to the areas af the city with underground cables,
stepped down to 15 kV locally, and then distributed again (the main
generation facilities are in Kozani, West Macedonia, and they burn brown
coal. Typical size of a unit is 300 MW, voltage 21 kV and current 10 kA
which is stepped up to 400 kV, 400 A line current for transmission to Athens
and Thessaloniki).



--
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
hordad AT otenet DOT gr

In article ,
Thomas Tornblom writes:
Residential power in Sweden is 400V 3 phase, main fuses normally 25A
or lower.

Room outlets are wired with one phase, neutral and ground to get 230V.

There is a smallish transformer station in the neighborhood which
probably powers two entire blocks. I would guess somewhere around 20-30
houses.

Similar in UK.

In most European countries, there's a single phase current limit,
above which you have to take a 3-phase supply. In the UK, that's
100A, so it's not very common to have a 3-phase supply although
you can ask for one if you want a 3-phase supply. In some other
European countries, the single phase limit is as low as 20A, so
just about everyone has a 3-phase supply.

Residential substation transformers (11kV down to 230/400) are
usually 1MVA, feeding a number of streets. A substation may have
more than one transformer in some cases (although they usually
only start out with one). Obviously, smaller transformers are
used where there aren't so many houses, and these are sometimes
pole mounted if the wiring is overhead.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article WMGTj.5083$ch1.2983@trndny09,
"James Sweet" writes:

It's not 110V, it's 240V, we simply split it with a grounded center tap
which gives 120V between each side and neutral, or 240V between the sides..

It's the regulation at 120V which people notice.
If you want to call it a 240V supply, then you
need to call EU supplies 400V or 415V. That's
equally misleading.

There's no transformer per house, except rural applications. Generally 5-10
houses are on each transformer, sometimes more. The problem with long runs
is that the voltage fluctuates substantially with large loads such as
central air conditioning. Standard North American residential service is 200
Amps 240V, I gather this is quite a bit larger than typical European
domestic stuff, so stretching it over 1km distance would require
prohibitively large cables or suffer from wide voltage swings. Makes more
sense to run 7200V down the street and locate a smallish transformer near
every half dozen houses.

The transformers are small in comparison, which gives poor
regulation in comparison (and as I said before, it's the
regulation at 120V which is the primary concern -- regulation
of 240V across 2 hots doesn't matter much for typical US 240V
loads).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

The transformers are small in comparison, which gives poor
regulation in comparison (and as I said before, it's the
regulation at 120V which is the primary concern -- regulation
of 240V across 2 hots doesn't matter much for typical US 240V
loads).



Regardless, the regulation is very good. I monitored mine for a while
and never saw it dip below 118V or go above 122V, most of the time it
was just about spot on 120V. A friend in the UK was doing the same on
his and it went as low as 224V and as high as 246V. We've done a lot of
comparing and have agreed that neither system is inherently better or
worse than the other, both have advantages and disadvantages.

In article ,
Andrew Gabriel wrote:
In article ,
Thomas Tornblom writes:
Residential power in Sweden is 400V 3 phase, main fuses normally 25A
or lower.

Room outlets are wired with one phase, neutral and ground to get 230V.

There is a smallish transformer station in the neighborhood which
probably powers two entire blocks. I would guess somewhere around 20-30
houses.

Similar in UK.

In most European countries, there's a single phase current limit,
above which you have to take a 3-phase supply. In the UK, that's
100A, so it's not very common to have a 3-phase supply although
you can ask for one if you want a 3-phase supply. In some other
European countries, the single phase limit is as low as 20A, so
just about everyone has a 3-phase supply.

Residential substation transformers (11kV down to 230/400) are
usually 1MVA, feeding a number of streets. A substation may have
more than one transformer in some cases (although they usually
only start out with one). Obviously, smaller transformers are
used where there aren't so many houses, and these are sometimes
pole mounted if the wiring is overhead.

or, as in the case of the transformer that feeds my house, pole mounted in
field with the output cables going underground immediately.

--
From KT24 - in "Leafy Surrey"

Using a RISC OS computer running v5.11

In alt.engineering.electrical Andrew Gabriel wrote:
| In article WMGTj.5083$ch1.2983@trndny09,
| "James Sweet" writes:
|
| It's not 110V, it's 240V, we simply split it with a grounded center tap
| which gives 120V between each side and neutral, or 240V between the sides..
|
| It's the regulation at 120V which people notice.
| If you want to call it a 240V supply, then you
| need to call EU supplies 400V or 415V. That's
| equally misleading.

The effect of loading and how it affects voltage depends on how well balanced
the TWO 120 volts phases are. If they are in balance, then the effect of the
loading on the voltage works as if you were considering the voltage at 240 volts.

If you get a three phase supply, and keep it balanced with the single phase
line to neutral loads, then the voltage regulation is going to be just like you
had loaded it with line-to-line loads, 208 volts in North America and 400 volts
in Europe.

If your neighborhood transformer is three phase, even if your home gets only
one phase of it (at just 230 volts), you still get advantage because other
homes will be distributed over other phases to keep it in balance.

But if you are comparing a single phase system, North American 120/240 with
three wires, vs. European 230 with two wires, it works out to be about the
same. The difference is we pay more for the extra wire, but we have a lower
line to ground shock risk (which isn't really much of an issue anymore with
improvements in safety in various ways such as GFI/RCD protection, better
rules on installations, etc).

So if you moved from Europe where you had 400/230 volts three phase in your
home, and came to North American and discovered we really had 480/277 volts
three phase, would that trouble you (assuming all appliances were designed
for that)?

--
|WARNING: Due to extreme spam, I no longer see any articles originating from |
| Google Groups. If you want your postings to be seen by more readers |
| you will need to find a different place to post on Usenet. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

? "Andrew Gabriel" ?????? ??? ??????
...
In article WMGTj.5083$ch1.2983@trndny09,
"James Sweet" writes:

It's not 110V, it's 240V, we simply split it with a grounded center tap
which gives 120V between each side and neutral, or 240V between the
sides..

It's the regulation at 120V which people notice.
If you want to call it a 240V supply, then you
need to call EU supplies 400V or 415V. That's
equally misleading.

There's no transformer per house, except rural applications. Generally
5-10
houses are on each transformer, sometimes more. The problem with long
runs
is that the voltage fluctuates substantially with large loads such as
central air conditioning. Standard North American residential service is
200
Amps 240V, I gather this is quite a bit larger than typical European
domestic stuff, so stretching it over 1km distance would require
prohibitively large cables or suffer from wide voltage swings. Makes more
sense to run 7200V down the street and locate a smallish transformer near
every half dozen houses.

The transformers are small in comparison, which gives poor
regulation in comparison (and as I said before, it's the
regulation at 120V which is the primary concern -- regulation
of 240V across 2 hots doesn't matter much for typical US 240V
loads).
The regulation, at least in Europe, is done at 150/15 kV substations and at
the HV side of the transformers, thus at 150 kV. Typical current for 2 x 25
MVA transformers is 150 A, 150 kV and of course secondary at 15 kV, 1500 A.
The regulation is done automatically with tap changers, live. The local
transformers at your neighborhood are fixed tap, 15 kV (they intend to
change everything to 20 kV).



--
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
hordad AT otenet DOT gr

In article ,
"Tzortzakakis Dimitrios" writes:

? "Andrew Gabriel" ?????? ??? ??????
...
In article WMGTj.5083$ch1.2983@trndny09,
"James Sweet" writes:

It's not 110V, it's 240V, we simply split it with a grounded center tap
which gives 120V between each side and neutral, or 240V between the
sides..

It's the regulation at 120V which people notice.
If you want to call it a 240V supply, then you
need to call EU supplies 400V or 415V. That's
equally misleading.

There's no transformer per house, except rural applications. Generally
5-10
houses are on each transformer, sometimes more. The problem with long
runs
is that the voltage fluctuates substantially with large loads such as
central air conditioning. Standard North American residential service is
200
Amps 240V, I gather this is quite a bit larger than typical European
domestic stuff, so stretching it over 1km distance would require
prohibitively large cables or suffer from wide voltage swings. Makes more
sense to run 7200V down the street and locate a smallish transformer near
every half dozen houses.

The transformers are small in comparison, which gives poor
regulation in comparison (and as I said before, it's the
regulation at 120V which is the primary concern -- regulation
of 240V across 2 hots doesn't matter much for typical US 240V
loads).
The regulation, at least in Europe, is done at 150/15 kV substations and at
the HV side of the transformers, thus at 150 kV. Typical current for 2 x 25
MVA transformers is 150 A, 150 kV and of course secondary at 15 kV, 1500 A.
The regulation is done automatically with tap changers, live. The local
transformers at your neighborhood are fixed tap, 15 kV (they intend to
change everything to 20 kV).

I'm referring to the transformer regulation (and also the LV
supply cable voltage drop) response to load changes. E.g. if
I switch on my 10kW shower, that's a 0.1% change against the
max load of my 1MVA substation transformer and therefore
makes no perceivable difference to the voltage in my house.
If I were to try that on a US 50kVA transformer, that load
is going to trigger a change of 20% of the transformer
regulation, which is much more significant and would
certainly be visible as a brightness change in light bulbs.

Having lived in both countries, I would say it's pretty much
expected in the US that lights dim even with quite moderate
loads coming on, whereas it's rare in the UK (generally only
in rural areas with long supply lines). There are many
contributory factors to this difference, but the 120V verses
240V (or if you must, 240V verses 415V) is ultimately the
underpinning reason.

Automatic tap changing in the HV network is completely
invisible to the residential consumer, as indeed it should
be.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In alt.engineering.electrical Andrew Gabriel wrote:

| I'm referring to the transformer regulation (and also the LV
| supply cable voltage drop) response to load changes. E.g. if
| I switch on my 10kW shower, that's a 0.1% change against the
| max load of my 1MVA substation transformer and therefore
| makes no perceivable difference to the voltage in my house.
| If I were to try that on a US 50kVA transformer, that load
| is going to trigger a change of 20% of the transformer
| regulation, which is much more significant and would
| certainly be visible as a brightness change in light bulbs.

What is the available fault current in these situations?

--
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
| Usenet from these places, find another Usenet provider ASAP. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

Tzortzakakis Dimitrios wrote:

The regulation, at least in Europe, is done at 150/15 kV substations and at
the HV side of the transformers, thus at 150 kV. Typical current for 2 x 25
MVA transformers is 150 A, 150 kV and of course secondary at 15 kV, 1500 A.
The regulation is done automatically with tap changers, live. The local
transformers at your neighborhood are fixed tap, 15 kV (they intend to
change everything to 20 kV).


So they have developed 100% efficient transformers?


--
http://improve-usenet.org/index.html


Use any search engine other than Google till they stop polluting USENET
with porn and junk commercial SPAM

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm

Andrew Gabriel wrote:

In article ,
"Tzortzakakis Dimitrios" writes:

? "Andrew Gabriel" ?????? ??? ??????
...
In article WMGTj.5083$ch1.2983@trndny09,
"James Sweet" writes:

It's not 110V, it's 240V, we simply split it with a grounded center tap
which gives 120V between each side and neutral, or 240V between the
sides..

It's the regulation at 120V which people notice.
If you want to call it a 240V supply, then you
need to call EU supplies 400V or 415V. That's
equally misleading.

There's no transformer per house, except rural applications. Generally
5-10
houses are on each transformer, sometimes more. The problem with long
runs
is that the voltage fluctuates substantially with large loads such as
central air conditioning. Standard North American residential service is
200
Amps 240V, I gather this is quite a bit larger than typical European
domestic stuff, so stretching it over 1km distance would require
prohibitively large cables or suffer from wide voltage swings. Makes more
sense to run 7200V down the street and locate a smallish transformer near
every half dozen houses.

The transformers are small in comparison, which gives poor
regulation in comparison (and as I said before, it's the
regulation at 120V which is the primary concern -- regulation
of 240V across 2 hots doesn't matter much for typical US 240V
loads).
The regulation, at least in Europe, is done at 150/15 kV substations and at
the HV side of the transformers, thus at 150 kV. Typical current for 2 x 25
MVA transformers is 150 A, 150 kV and of course secondary at 15 kV, 1500 A.
The regulation is done automatically with tap changers, live. The local
transformers at your neighborhood are fixed tap, 15 kV (they intend to
change everything to 20 kV).

I'm referring to the transformer regulation (and also the LV
supply cable voltage drop) response to load changes. E.g. if
I switch on my 10kW shower, that's a 0.1% change against the
max load of my 1MVA substation transformer and therefore
makes no perceivable difference to the voltage in my house.
If I were to try that on a US 50kVA transformer, that load
is going to trigger a change of 20% of the transformer
regulation, which is much more significant and would
certainly be visible as a brightness change in light bulbs.

Having lived in both countries, I would say it's pretty much
expected in the US that lights dim even with quite moderate
loads coming on, whereas it's rare in the UK (generally only
in rural areas with long supply lines). There are many
contributory factors to this difference, but the 120V verses
240V (or if you must, 240V verses 415V) is ultimately the
underpinning reason.


The central air kicks on without my lights dimming, and I am in North
Central Florica.


Automatic tap changing in the HV network is completely
invisible to the residential consumer, as indeed it should
be.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]


--
http://improve-usenet.org/index.html


Use any search engine other than Google till they stop polluting USENET
with porn and junk commercial SPAM

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm

The central air kicks on without my lights dimming, and I am in North
Central Florica.



Mine dim slightly for an instant when my 3 ton heat pump kicks in, it's
only noticeable with the few incandescent lights left in the house
though. The LRA on that thing is something like 90A. I think most of the
drop must be in the 50' or so of 2/0 AL wire between the meter base and
the transformer though as they don't seem to dim at all from any of the
neighbors.

In article ,
"Michael A. Terrell" wrote:

So they have developed 100% efficient transformers?

Yep, their called Super Conducting Transformers, and they have been
around the LABS, for about 15 years now. Only one BIG problem with them.
They only work at 20 Degrees Kevin or lower in temperature.

In alt.engineering.electrical Michael A. Terrell wrote:

| The central air kicks on without my lights dimming, and I am in North
| Central Florica.

I bet it's on its own branch circuit, too.

--
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
| Usenet from these places, find another Usenet provider ASAP. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

wrote:
In alt.engineering.electrical Michael A. Terrell wrote:

| The central air kicks on without my lights dimming, and I am in North
| Central Florica.

I bet it's on its own branch circuit, too.



Of course it is, that's the only legal way to do it.

wrote:

In alt.engineering.electrical Michael A. Terrell wrote:

| The central air kicks on without my lights dimming, and I am in North
| Central Florica.

I bet it's on its own branch circuit, too.


So what? The meter is on a pole on one side of the driveway ( two
feet from the property line, because Progress Energy does not allow
drops to cross a driveway anymore.), and an outdoor breaker box is on
the remaining four foot stump of the old pole on the other side of the
paved drive, about 40 feet away. The 60 A breaker for the AC is in that
box, along with the 100 A main breaker that is used as a disconnect for
the house. That box is over 125 feet from the pole pig, on a 150 A
service. That box also feeds another underground line to the laundry
building,, and well pump. The main breaker box for the house is another
20 feet from the outdoor box. Now, tell me how it can have no effect on
the line voltage. I still see very little flickering, usually only on
hot summer days when everyone in the subdivision is using the AC and
their kitchen stoves at the same time. That is usually followed by a
blown 60 A fuse in the 7200 volt line, feeding my street.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

In alt.engineering.electrical Michael A. Terrell wrote:
| wrote:
|
| In alt.engineering.electrical Michael A. Terrell wrote:
|
| | The central air kicks on without my lights dimming, and I am in North
| | Central Florica.
|
| I bet it's on its own branch circuit, too.
|
|
| So what? The meter is on a pole on one side of the driveway ( two
| feet from the property line, because Progress Energy does not allow
| drops to cross a driveway anymore.), and an outdoor breaker box is on
| the remaining four foot stump of the old pole on the other side of the
| paved drive, about 40 feet away. The 60 A breaker for the AC is in that
| box, along with the 100 A main breaker that is used as a disconnect for
| the house. That box is over 125 feet from the pole pig, on a 150 A
| service. That box also feeds another underground line to the laundry
| building,, and well pump. The main breaker box for the house is another
| 20 feet from the outdoor box. Now, tell me how it can have no effect on
| the line voltage. I still see very little flickering, usually only on
| hot summer days when everyone in the subdivision is using the AC and
| their kitchen stoves at the same time. That is usually followed by a
| blown 60 A fuse in the 7200 volt line, feeding my street.

If it were not on its own branch circuit, that would (in addition to being
a code violation) more likely cause other stuff (whatever else is on the
same circuit) to experience dimming. The fact that it is onis own branch
circuit doesn't mean there isn't a big voltage drop. But only the A/C would
be getting it, and it wouldn't matter (much).

It can have no (or very little that cannot be noticed) effect on the line
voltage because you have good wiring and the transformer has a high enough
capacity and low enough impedance. This is stuff you know.

Blowing a 60 amp fuse at 7200 volts is not a small neighborhood.

I can understand them not wanting to go overheard over a driveway. RVs can
be a fun place for kids to climb on (even if terribly unsafe). Or they can
catch fire (I've seen that happen and it _was_ a case of a service drop over
a driveway that faulted when the insulation melted off).

--
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
| Usenet from these places, find another Usenet provider ASAP. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

wrote:

In alt.engineering.electrical Michael A. Terrell wrote:
| wrote:
|
| In alt.engineering.electrical Michael A. Terrell wrote:
|
| | The central air kicks on without my lights dimming, and I am in North
| | Central Florica.
|
| I bet it's on its own branch circuit, too.
|
|
| So what? The meter is on a pole on one side of the driveway ( two
| feet from the property line, because Progress Energy does not allow
| drops to cross a driveway anymore.), and an outdoor breaker box is on
| the remaining four foot stump of the old pole on the other side of the
| paved drive, about 40 feet away. The 60 A breaker for the AC is in that
| box, along with the 100 A main breaker that is used as a disconnect for
| the house. That box is over 125 feet from the pole pig, on a 150 A
| service. That box also feeds another underground line to the laundry
| building,, and well pump. The main breaker box for the house is another
| 20 feet from the outdoor box. Now, tell me how it can have no effect on
| the line voltage. I still see very little flickering, usually only on
| hot summer days when everyone in the subdivision is using the AC and
| their kitchen stoves at the same time. That is usually followed by a
| blown 60 A fuse in the 7200 volt line, feeding my street.

If it were not on its own branch circuit, that would (in addition to being
a code violation) more likely cause other stuff (whatever else is on the
same circuit) to experience dimming. The fact that it is onis own branch
circuit doesn't mean there isn't a big voltage drop. But only the A/C would
be getting it, and it wouldn't matter (much).

It can have no (or very little that cannot be noticed) effect on the line
voltage because you have good wiring and the transformer has a high enough
capacity and low enough impedance. This is stuff you know.

Blowing a 60 amp fuse at 7200 volts is not a small neighborhood.


48 lots, 47 with homes. That gives 7200*60/240 or 1800 A @ 240 V for
47 homes gives an average 38.29 A per home which is the reason that fuse
can blow more than once a week, along with it's explosive discharge that
sounds like a shotgun every time it blows.


I can understand them not wanting to go overheard over a driveway. RVs can
be a fun place for kids to climb on (even if terribly unsafe). Or they can
catch fire (I've seen that happen and it _was_ a case of a service drop over
a driveway that faulted when the insulation melted off).


At one time there were two meters on the property, because the
original owner had a blacksmith shop in the 1200 Sq Ft garage.



--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

In alt.engineering.electrical Michael A. Terrell wrote:
| wrote:
|
| In alt.engineering.electrical Michael A. Terrell wrote:
| | wrote:
| |
| | In alt.engineering.electrical Michael A. Terrell wrote:
| |
| | | The central air kicks on without my lights dimming, and I am in North
| | | Central Florica.
| |
| | I bet it's on its own branch circuit, too.
| |
| |
| | So what? The meter is on a pole on one side of the driveway ( two
| | feet from the property line, because Progress Energy does not allow
| | drops to cross a driveway anymore.), and an outdoor breaker box is on
| | the remaining four foot stump of the old pole on the other side of the
| | paved drive, about 40 feet away. The 60 A breaker for the AC is in that
| | box, along with the 100 A main breaker that is used as a disconnect for
| | the house. That box is over 125 feet from the pole pig, on a 150 A
| | service. That box also feeds another underground line to the laundry
| | building,, and well pump. The main breaker box for the house is another
| | 20 feet from the outdoor box. Now, tell me how it can have no effect on
| | the line voltage. I still see very little flickering, usually only on
| | hot summer days when everyone in the subdivision is using the AC and
| | their kitchen stoves at the same time. That is usually followed by a
| | blown 60 A fuse in the 7200 volt line, feeding my street.
|
| If it were not on its own branch circuit, that would (in addition to being
| a code violation) more likely cause other stuff (whatever else is on the
| same circuit) to experience dimming. The fact that it is onis own branch
| circuit doesn't mean there isn't a big voltage drop. But only the A/C would
| be getting it, and it wouldn't matter (much).
|
| It can have no (or very little that cannot be noticed) effect on the line
| voltage because you have good wiring and the transformer has a high enough
| capacity and low enough impedance. This is stuff you know.
|
| Blowing a 60 amp fuse at 7200 volts is not a small neighborhood.
|
|
| 48 lots, 47 with homes. That gives 7200*60/240 or 1800 A @ 240 V for
| 47 homes gives an average 38.29 A per home which is the reason that fuse
| can blow more than once a week, along with it's explosive discharge that
| sounds like a shotgun every time it blows.

Yup, big neighborhood. It wouldn't take much after 47 home central A/C's
are running to go over the fuse rating. Any guess what the curve on that
fuse is? E.g. how long can you go at 105%? 125%?

--
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
| Usenet from these places, find another Usenet provider ASAP. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

? "Michael A. Terrell" ?????? ??? ??????
m...

Tzortzakakis Dimitrios wrote:

The regulation, at least in Europe, is done at 150/15 kV substations and
at
the HV side of the transformers, thus at 150 kV. Typical current for 2 x
25
MVA transformers is 150 A, 150 kV and of course secondary at 15 kV, 1500
A.
The regulation is done automatically with tap changers, live. The local
transformers at your neighborhood are fixed tap, 15 kV (they intend to
change everything to 20 kV).


So they have developed 100% efficient transformers?

.net/ISP.htm
Of course not:-) These are approximate figures (like the 21 kV 10 kA
alternator, which in fact is 9823 A 21200 volts or whatever). But the
efficiency of large transformers or transmission lines, when they operate at
optimum is 99%.




--
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
hordad AT otenet DOT gr

? "daestrom" ?????? ??? ??????
...

"Tzortzakakis Dimitrios" wrote in message
...

? "Andrew Gabriel" ?????? ??? ??????
...
snip
The transformers are small in comparison, which gives poor
regulation in comparison (and as I said before, it's the
regulation at 120V which is the primary concern -- regulation
of 240V across 2 hots doesn't matter much for typical US 240V
loads).
The regulation, at least in Europe, is done at 150/15 kV substations and
at the HV side of the transformers, thus at 150 kV. Typical current for 2
x 25 MVA transformers is 150 A, 150 kV and of course secondary at 15 kV,
1500 A. The regulation is done automatically with tap changers, live. The
local transformers at your neighborhood are fixed tap, 15 kV (they intend
to change everything to 20 kV).



You're confusing two uses of the term 'regulation'. Tap changers and
voltage regulators actively sense the terminal voltage and adjust
'something' to maintain the voltage within some design limit. That's a
'regulator' and provides 'regulation' of the sensed voltage.

I know that, but it was a temptation to post this:-)
But 'regulation' also is a term used to describe the inherent voltage drop
in some devices. For example, if you review DC generators, you'll find
that simple shunt-wound generators have fairly good 'regulation' and their
output voltage only drops a few percent from no-load to full-load when
supplied with a fixed field. A cumulatively-compound DC generator (which
has a series field and a shunt field), can have a nearly flat voltage
curve from no-load to full-load with just a fixed shunt excitation, or
even have a voltage rise depending on the degree of compounding. (of
course, an active voltage regulator can counteract whatever inherent
regulation a machine may have)

A shame that Tesla won the infamous "battle" and we don't have DC:-() But
then, we would be having a power plant at each neighborhood, instead of the
300 MW ones.
In the case of simple fixed-tap transformers, the term 'regulation' can be
used to describe how much the output terminal voltage changes from no-load
to full-load if the primary voltage is held constant. This use is less
than perfect as it is much better to use the transformer's impedance along
with the load's power factor to get a more precise answer.

In the US, voltage regulation is accomplished with load-tap-changers,
capacitor banks, and other 'voltage support services'.
We have here capacitor banks, too, connected at the LV side of the
substation, 15 kV line-to-line voltage.
But just like in
Europe, it is done at the substation or higher level and not done at the
typical distribution transformer. There are exceptions for rural areas
though where the line length of the primary leads to some issues.

daestrom
P.S. In the US, a 'tap-changer' may be built for either for unloaded or
loaded operation. The 'unloaded' type can not be stepped to another tap
while there is load on the unit (although it can still be energized).
It's switch contacts cannot interrupt load though, so if you try to move
it while loaded, you can burn up the tap-changer. The classic
'load-tap-changer' is actually several switches that are controlled in a
precise sequence to shift the load from one tap of the transformer to
another while not interrupting the load current.

P.P.S. Load tap changers typically have a significant time-delay built
into the controls so they do not 'hunt' or respond to short drops in
voltage such as starting a large load. 15 seconds to several minutes is
typical. So even with load-tap-changers, starting a single load that is a
high percentage of the system capacity will *still* result in a voltage
dip.

Yeah, the ones we have here are automatic, live and even have a shaft for
manual control.

I know, I know, my answer was a bit provocative:-) And of course there are
DC regulators.... You're talking about DC generators;the one a 300 MW uses
for excitation is 220 V, 1000 A DC and probably shunt field. I have seen
here in some machine shops the old type welding generator, which is a 3
phase induction motor coupled to (usually) a compound field DC generator,
which provides the welding current. The modern ones are, maybe, not larger
than a shoe box and powered by a higher wattage 230 V 16 A receptacle.
(Usual receptacles are 230 V 10 A;16 A for washing machines, dryers and the
like).



--
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
hordad AT otenet DOT gr

"daestrom" writes:


P.S. In the US, a 'tap-changer' may be built for either for unloaded or
loaded operation. The 'unloaded' type can not be stepped to another tap
while there is load on the unit (although it can still be energized). It's
switch contacts cannot interrupt load though, so if you try to move it while
loaded, you can burn up the tap-changer. The classic 'load-tap-changer' is
actually several switches that are controlled in a precise sequence to shift
the load from one tap of the transformer to another while not interrupting
the load current.

P.P.S. Load tap changers typically have a significant time-delay built into
the controls so they do not 'hunt' or respond to short drops in voltage such
as starting a large load. 15 seconds to several minutes is typical. So
even with load-tap-changers, starting a single load that is a high
percentage of the system capacity will *still* result in a voltage dip.

Are the load tap generators configured make-before-break?
Break-before-make would mean a (very short) power outage every activation
but make-before-break would mean a momentarily short-circuited winding and
the break would involve interrupting a large short circuit current.

Certainly modern ones likely use thyristors and zero crossing detectors.

When I was a kid living in a rather rural area, there would be a pair of
these on poles every few miles, connected open delta. (all transformer
primaries were connected phase-phase then).

In alt.engineering.electrical Tzortzakakis Dimitrios wrote:

| A shame that Tesla won the infamous "battle" and we don't have DC:-() But
| then, we would be having a power plant at each neighborhood, instead of the
| 300 MW ones.

And the latter make easy terrorism targets, too.


| I know, I know, my answer was a bit provocative:-) And of course there are
| DC regulators.... You're talking about DC generators;the one a 300 MW uses
| for excitation is 220 V, 1000 A DC and probably shunt field. I have seen
| here in some machine shops the old type welding generator, which is a 3
| phase induction motor coupled to (usually) a compound field DC generator,
| which provides the welding current. The modern ones are, maybe, not larger
| than a shoe box and powered by a higher wattage 230 V 16 A receptacle.
| (Usual receptacles are 230 V 10 A;16 A for washing machines, dryers and the
| like).

You don't use 400 V for anything heavy duty like an oven?

--
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
| Usenet from these places, find another Usenet provider ASAP. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

In writes:

In alt.engineering.electrical Tzortzakakis Dimitrios wrote:

| A shame that Tesla won the infamous "battle" and we don't have DC:-() But
| then, we would be having a power plant at each neighborhood, instead of the
| 300 MW ones.

And the latter make easy terrorism targets, too.

And so does that 20 gallons of gasoline parked
in front of your house. And that 500 gallons
of diesel fuel in your basment. And that 20,000
or so gallons in the nearby gas station.

Yawn.

--
__________________________________________________ ___
Knowledge may be power, but communications is the key

[to foil spammers, my address has been double rot-13 encoded]

In alt.engineering.electrical Michael Moroney wrote:

| Are the load tap generators configured make-before-break?
| Break-before-make would mean a (very short) power outage every activation
| but make-before-break would mean a momentarily short-circuited winding and
| the break would involve interrupting a large short circuit current.

I wonder how much regulation could be managed through the use of variable
leakage inductance in the transformer windings.


| Certainly modern ones likely use thyristors and zero crossing detectors.

With zero crossing detection, then the switching is not happening on all phases
at the same time.

--
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
| Usenet from these places, find another Usenet provider ASAP. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

wrote:
In alt.engineering.electrical Tzortzakakis Dimitrios wrote:

| A shame that Tesla won the infamous "battle" and we don't have DC:-() But
| then, we would be having a power plant at each neighborhood, instead of the
| 300 MW ones.

And the latter make easy terrorism targets, too.


| I know, I know, my answer was a bit provocative:-) And of course there are
| DC regulators.... You're talking about DC generators;the one a 300 MW uses
| for excitation is 220 V, 1000 A DC and probably shunt field. I have seen
| here in some machine shops the old type welding generator, which is a 3
| phase induction motor coupled to (usually) a compound field DC generator,
| which provides the welding current. The modern ones are, maybe, not larger
| than a shoe box and powered by a higher wattage 230 V 16 A receptacle.
| (Usual receptacles are 230 V 10 A;16 A for washing machines, dryers and the
| like).

You don't use 400 V for anything heavy duty like an oven?



In North America, 240V 50A is pretty standard for ovens, some are 40A,
clothes dryers are 30A, most other stuff plugs into a 15A 120V receptacle.

writes:

In alt.engineering.electrical Michael Moroney wrote:

| Are the load tap generators configured make-before-break?
| Break-before-make would mean a (very short) power outage every activation
| but make-before-break would mean a momentarily short-circuited winding and
| the break would involve interrupting a large short circuit current.

I wonder how much regulation could be managed through the use of variable
leakage inductance in the transformer windings.

Good question.

| Certainly modern ones likely use thyristors and zero crossing detectors.

With zero crossing detection, then the switching is not happening on all phases
at the same time.

Since the ones I've seen are 3 (or 2) independent autotransformers, this
is true without zero crossing detectors, and the power supplied may not
always be of equal voltages 120 degrees apart.

In article ,
writes:

You don't use 400 V for anything heavy duty like an oven?

Some parts of Europe do. You find ovens can be strapped to
run from one or two phases, depending what's available on
the premises. Some parts of Europe use 3-phase 400V domestic
water heaters.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In sci.electronics.repair jakdedert wrote:
I'm a little confused about a 230 volt circuit. In what part of the
world does the utility supply 230v?

Continental Europe used to have 220 volts (before that it was 127 volts in
some places), the UK used to have 240 volts. Nowadays, the common voltage
is 230 volts -10% +6%.

--
Met vriendelijke groet,

Maarten Bakker.

danny burstein wrote:

And the latter make easy terrorism targets, too.

And so does that 20 gallons of gasoline parked
in front of your house. And that 500 gallons
of diesel fuel in your basment. And that 20,000
or so gallons in the nearby gas station.

Yawn.


http://www.triallogs.com/index.php?/...6.0/attach,87/

wrote:

In sci.electronics.repair jakdedert wrote:
I'm a little confused about a 230 volt circuit. In what part of the
world does the utility supply 230v?

Continental Europe used to have 220 volts (before that it was 127 volts in
some places), the UK used to have 240 volts. Nowadays, the common voltage
is 230 volts -10% +6%.


In other words, nothing has changed. They just wrote sloppier specs.


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Use any search engine other than Google till they stop polluting USENET
with porn and junk commercial SPAM

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm

In alt.engineering.electrical James Sweet wrote:
|
| wrote:
| In alt.engineering.electrical Tzortzakakis Dimitrios wrote:
|
| | A shame that Tesla won the infamous "battle" and we don't have DC:-() But
| | then, we would be having a power plant at each neighborhood, instead of the
| | 300 MW ones.
|
| And the latter make easy terrorism targets, too.
|
|
| | I know, I know, my answer was a bit provocative:-) And of course there are
| | DC regulators.... You're talking about DC generators;the one a 300 MW uses
| | for excitation is 220 V, 1000 A DC and probably shunt field. I have seen
| | here in some machine shops the old type welding generator, which is a 3
| | phase induction motor coupled to (usually) a compound field DC generator,
| | which provides the welding current. The modern ones are, maybe, not larger
| | than a shoe box and powered by a higher wattage 230 V 16 A receptacle.
| | (Usual receptacles are 230 V 10 A;16 A for washing machines, dryers and the
| | like).
|
| You don't use 400 V for anything heavy duty like an oven?
|
|
|
| In North America, 240V 50A is pretty standard for ovens, some are 40A,
| clothes dryers are 30A, most other stuff plugs into a 15A 120V receptacle.

But we don't have an easy option for any higher voltage. In many parts of
Europe, three phase 400/230V is delivered to homes. Then using 400V, either
2 lines or all 3 lines, is an option.

--
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
| Usenet from these places, find another Usenet provider ASAP. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

In alt.engineering.electrical daestrom wrote:
|
| wrote in message
| ...
| In alt.engineering.electrical Michael Moroney
| wrote:
|
| | Are the load tap generators configured make-before-break?
| | Break-before-make would mean a (very short) power outage every
| activation
| | but make-before-break would mean a momentarily short-circuited winding
| and
| | the break would involve interrupting a large short circuit current.
|
| I wonder how much regulation could be managed through the use of variable
| leakage inductance in the transformer windings.
|
|
| I suppose you could, but increasing leakage inductance means you're
| increasing losses aren't you? Just a percent or two on a unit rated for 250
| MVA can be too much to tolerate.

Isn't it just inductance in series? Shouldn't that just be a phase shift as
seen from the primary side?

--
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
| Usenet from these places, find another Usenet provider ASAP. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

----------------------------
"Michael Moroney" wrote in message
...
"daestrom" writes:


P.S. In the US, a 'tap-changer' may be built for either for unloaded or
loaded operation. The 'unloaded' type can not be stepped to another tap
while there is load on the unit (although it can still be energized).
It's
switch contacts cannot interrupt load though, so if you try to move it
while
loaded, you can burn up the tap-changer. The classic 'load-tap-changer'
is
actually several switches that are controlled in a precise sequence to
shift
the load from one tap of the transformer to another while not interrupting
the load current.

P.P.S. Load tap changers typically have a significant time-delay built
into
the controls so they do not 'hunt' or respond to short drops in voltage
such
as starting a large load. 15 seconds to several minutes is typical. So
even with load-tap-changers, starting a single load that is a high
percentage of the system capacity will *still* result in a voltage dip.

Are the load tap generators configured make-before-break?
Break-before-make would mean a (very short) power outage every activation
but make-before-break would mean a momentarily short-circuited winding and
the break would involve interrupting a large short circuit current.
--------
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).
--------------

Certainly modern ones likely use thyristors and zero crossing detectors.
-------------
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. --------------------------


When I was a kid living in a rather rural area, there would be a pair of
these on poles every few miles, connected open delta. (all transformer
primaries were connected phase-phase then).

"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.
--

Don Kelly
remove the X to answer