Frequency and the world

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Besoeker

Besoeker

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JJWalecka said:
Frequency and the world, I thought just the US and Canadian used sixty hertz. I found this interesting

JJ
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Yes, I think choice of frequency is interesting and there is probably a historical - and a compromise. There is no one size fits all solution.
Switch mode power supplies use high frequency to get component size (and cost) down. HVDC transmission, in effect zero frequency, is used to reduce losses and voltage drop.
Being a Brit, I'm from one of the 50Hz countries. I suppose it makes frequency to period calculations a bit simpler - and transformers bigger.
One thing I would say in favor of the UK system is that it is simpler with everything in your house running from one voltage, nominally 230Vac single phase.
 
iwire

iwire

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Besoeker said:
One thing I would say in favor of the UK system is that it is simpler with everything in your house running from one voltage, nominally 230Vac single phase.
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I certainly agree that from an outsiders perspective having two voltages in homes would be a problem, but having grown up with this it is not even noticed. :smile:

The large majority of American home appliances are 120 volt.

Air conditioning units and heating units are usually where we use 208 or 240 in a dwelling unit.

Our commercial buildings will often have four voltages for lighting and power, 480, 277, 208 and 120. Its nice to have choices. :cool:

I have also been involved in a few buildings here in the US that had both 50 and 60 Hz systems as they made equipment for foreign markets and needed both systems for testing purposes. Motor generator sets where used to make the 50 Hz.
 
JJWalecka

JJWalecka

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I woke up this morning wondering about the advantages of having a single voltage in a home as opposed to two as in the US.
Is it safer to have a lower voltage in a residence?
With a higher voltage the current is lower. What is the standard over current devices in the rest ofthe world?

JJ
 
Besoeker

Besoeker

Senior Member
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UK
JJWalecka said:
I woke up this morning wondering about the advantages of having a single voltage in a home as opposed to two as in the US.
Is it safer to have a lower voltage in a residence?
With a higher voltage the current is lower. What is the standard over current devices in the rest ofthe world?
JJ
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In UK for domestic use, appliances are fitted wth a 13A plug which has a built in cartridge fuse. If an appliance fails it takes out that fuse rather than the supply breaker/fuse feeding everything on that particular circuit.
But one of the main advantages is that there is just one supply voltage.
 
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JJWalecka

JJWalecka

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New England
Really!!? Thats interesting. Do you know, off hand, what size beakers are in a dwelling panel? Would a lamp have the same fuse? Thanks for your time.

JJ
 
Besoeker

Besoeker

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iwire said:
I certainly agree that from an outsiders perspective having two voltages in homes would be a problem, but having grown up with this it is not even noticed. :smile:
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I'm not entirely an outsider. We have a residence in UK and another in the US so I am somewhat familiar with both systems.

iwire said:
The large majority of American home appliances are 120 volt.
Air conditioning units and heating units are usually where we use 208 or 240 in a dwelling unit.
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That's it in a nutshell.;)
iwire said:
Our commercial buildings will often have four voltages for lighting and power, 480, 277, 208 and 120. Its nice to have choices. :cool:
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But what advantage does that choice give? Here there is effectively one system. 400 3-ph and 230 1-ph derived from phase to neutral of the 400V for most LV applications.;
For sure, other voltages are used for specific applications. A few examples:
Many industrial sites proscribe the use of power tools at anything above 110Vac. So 110V is produced locally from 230/110 transformers.
We are currently building some 690V variable speed drives. There is a unit transformer 15kV to 690V
We have just completed the commissioning of a 20kA rectifier system that has a 630V input from a dedicated 11kV to 630V transformer.
But these are the oddballs.

iwire said:
I have also been involved in a few buildings here in the US that had both 50 and 60 Hz systems as they made equipment for foreign markets and needed both systems for testing purposes. Motor generator sets where used to make the 50 Hz.
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We did it the other way round.
We recently (August) completed a couple of static exciters for rotary frequency converters. They were 50 to 60 of course for US warships docked in a UK naval base. And 6.6kV, 5MW each.
Big noisy beasts too.
 
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dbuckley

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Location
Canterbury, New Zealand
JJWalecka said:
Really!!? Thats interesting. Do you know, off hand, what size beakers are in a dwelling panel? Would a lamp have the same fuse?JJ
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In the UK the standard socket outlet is rated at 13A, so good for a 3KW load. The breaker for the socket is 32A. The fuse in the plug can be any value betweem 1A and 13A with 3A and 13A being the preferred ratings.

In my opinion, this is the best system on the planet, simply because if you have something like a bedside lamp with weedy wire on it, in the US (and New Zealand where I live, and just about everywhere else) that wire is "protected" by a 20A breaker, so its not protected at all against overload, whereas in the UK a 3A fuse protects the wire. So much better.

And there is one big advantage of 240V outlets rather than 110V in the home - the four slice toaster can actually toast four slices in less than a week :) The big advantage of 120V is that halogen lamps look better as the filament is smaller and heavier. Other than that, theres no real difference...

Actually, there is one big difference that you would notice - in the USA there is about a zillion different sorts of NEMA receptacles whereas in 240V countries they have the standard domestic socket whatever that might be, and then CEEFORM connectors for everything else up to 125A.
 
JJWalecka

JJWalecka

Senior Member
Location
New England
"I'll bet you miss Tommy Boy!!" Steelersman

Don't want to talk about it...........

"Sacked 47 times last season, Roethlisberger is on pace for almost 58 this season, which would set a Steelers record."

I hope all stays well for you too. LOL

JJ
 
steelersman

steelersman

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Location
Lake Ridge, VA
JJWalecka said:
"Sacked 47 times last season, Roethlisberger is on pace for almost 58 this season, which would set a Steelers record."
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If it makes you feel any better Matt Cassel is second behind Big Ben for sacks per drop backs. :)
 
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