ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 2 3 [4]   Go Down

Author Topic: Power Outlets Worldwide  (Read 15534 times)

Jonathan Johnson

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3120
  • Southwest Washington (state, not DC)
Re: Power Outlets Worldwide
« Reply #30 on: December 25, 2013, 10:32:59 pm »

How is the combined 120/240 dryer supply used?  120 for control circuits and 240 for heater elements?   If so, why not run it all on 240?

My understanding -- which may be wrong -- of the history of power in the United States is that Edison's DC power distribution system generated 110V (at the generator) and due to resistance losses in the transmission, the voltage was around 100V at the point of use. Light bulbs -- the primary product of Edison's company -- were designed for 100-120V. At the time, many homes weren't even wired with 240V service; only a single hot leg (110V) was installed to the home. In order to reduce the size of the copper wires necessary, both +110 and -110 service was available, with a "neutral" 0V third line. This 110V legacy of Edison's light bulbs eventually carried over into the AC distribution system, which was spec'd to provide between 110 and 125V at the point of use, with a nominal 117V.

Since both +110V and -110V were available, manufacturers took advantage of this and made 220V heating appliances that provided greater wattage than 110V could provide without the need to increase the wire size in the home. In the United States, the installed base of 110-125V devices is so large that it could be an economic disaster to force reconfiguration of wiring in homes and businesses plus replacement of billions of appliances to meet a single, 240V standard.

It's interesting to note that the voltage specifications have gradually increased, as the distribution system has increased its capacity. Where originally the expectation was to deliver 100V to the point of use, that specification gradually increased to 110V then 115V then 120V. Though the nominal voltage is currently 120V, it is not uncommon to measure voltages in excess of that, up to 125V. Likewise, the "high-voltage" service specification increased from 200V to 220V to 230V to 240V with a "maximum" now of 250V. If you look at very old receptacles and switchgear, you'll see some rated for "110/220V" or "115/230V," some "120/240V." It now is all rated "125/250V."

Most current appliances and motors without universal-voltage switching power supplies now are designed to safely accept up to 125V.
Logged
Stop confusing the issue with facts and logic!

Jonathan Johnson

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3120
  • Southwest Washington (state, not DC)
Re: Power Outlets Worldwide
« Reply #31 on: December 25, 2013, 10:41:20 pm »

Having brass/silver screws to determine live and neutral seems strange to me as it's the sort of thing which most people are not going to notice.

I never trust the color of the screws; instead I go by position. I've actually held in my hands a 120V duplex receptacle in which the brass and silver screws were reversed by the factory. Of course, I wired it correctly, hot to the narrow slot and neutral to the wide slot.

When I wire a plug onto the end of a cord, I still go by position, not by color.

Anymore, I don't even pay attention to the color of the screws. If there is any doubt which screw goes to which contact, I meter it.
Logged
Stop confusing the issue with facts and logic!

Kevin Graf

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 331
Re: Power Outlets Worldwide
« Reply #32 on: December 25, 2013, 10:51:17 pm »

And in a parallel universe.

"Anyone know why voltage 120/240 is referred to as 110/220"

http://forums.mikeholt.com/showthread.php?t=158461
Logged
Speedskater

Steve M Smith

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3328
  • Isle of Wight - England
Re: Power Outlets Worldwide
« Reply #33 on: December 26, 2013, 02:06:23 am »

Most of Manhattan’s DC service had long before been replaced by the utility’s alternating current (AC) system, pioneered by Nikola Tesla

http://theoatmeal.com/comics/tesla


Steve.
Logged

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3361
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: Power Outlets Worldwide
« Reply #34 on: December 26, 2013, 07:23:03 am »

Logged
Mike Sokol
mike@noshockzone.org
www.NoShockZone.org

Cailen Waddell

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1428
Re: Power Outlets Worldwide
« Reply #35 on: December 26, 2013, 09:15:52 am »


They do in fact use 120-volts for the drum motor and timer control, then save the 240-volts for the heater element. I think it's because the manufacturer can use the same 120-volt motor on its washers as well as dryers. Same for all power supply transformers to run the electronics. It's only when you get into pro-sound gear that is planned to be used in various countries that you'll see auto-switching suppliers rated from 90 to 250 volt at 50 or 60 Hz. I think that about covers all worldwide possibilities.

If memory serves, the original 3-wire bootleg grounded dryer outlet was originally a "temporary" exclusion sometime in the 60's to save money for home "electrification" which was becoming popular at the time. There was a lot of fighting between the electric and natural gas industries for the home power supplier. That's about the same time that aluminum wiring was allowed (and for the same reason). But that turned into a horrible cluster with lots of fires started in the walls of home due to aluminum oxide high resistance, as well as electricians using non-aluminum rated receptacles. Did the UK (or anywhere else) go through the crazy aluminum craze the USA did?

We are renovating our kitchen for Christmas (which is a whole 'nother thread) but I pulled out our dryer, which had an adapter I made to bootleg the ground as we have an old 3 prong dryer outlet....  Anyway, I decided to replace the cord and install a 3 prong dryer cord set, opened the dryer and discovered that when originally wired with the 4 conductor cord set, by the appliance deliver guys (my mistake to let them do that), they had never pulled the bootleg grounding wire out of the dryer, so it was destined to be bootleg grounded no matter where we plugged it in...  I could say I'm surprised they didn't know to pull it when the 4 conductor cord set was installed but I'm not....

I find it interesting that a house built in '84, with a good electrical panel and correct grounding on outlets still got a 3 conductor bootleg dryer outlet. It is only 10 feet from the panel....
Logged

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3361
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: Power Outlets Worldwide
« Reply #36 on: December 26, 2013, 09:43:12 am »

they had never pulled the bootleg grounding wire out of the dryer, so it was destined to be bootleg grounded no matter where we plugged it in...  I could say I'm surprised they didn't know to pull it when the 4 conductor cord set was installed but I'm not....

I'm not surprised either. And the same goes for double-bonding the Ground and Neutral bus in sub-panels. That causes neutral currents to flow in the safety ground wires which causes a voltage difference between two different outlet grounds. That voltage difference between the outlet grounds is what causes ground loop currents in sound systems which can result in ground-loop hum (the pin-1 problem).

I'm now working on a table top experiment that will show how these neutral contaminated grounds can allow bass transients (such as kick drum and bass) to modulate ground-loop-hum in sound systems, causing a distortion I call GLID (Ground Loop Intermodulation Distortion). I'm fairly certain that GLID is responsible for "fuzzy" or "loss of bass definition" in some (many?) live and studio sound systems.

But there's lots more testing and listening to be done. Once I get the experiment and demonstration designed and some empirical data gathered, I'll see if a few of you would like to do a peer review on my findings. Too much fun. ;)
Logged
Mike Sokol
mike@noshockzone.org
www.NoShockZone.org

Cailen Waddell

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1428
Re: Power Outlets Worldwide
« Reply #37 on: December 26, 2013, 09:48:43 am »



I'm now working on a table top experiment that will show how these neutral contaminated grounds can allow bass transients (such as kick drum and bass) to modulate ground-loop-hum in sound systems, causing a distortion I call GLID (Ground Loop Intermodulation Distortion). I'm fairly certain that GLID is responsible for "fuzzy" or "loss of bass definition" in some (many?) live and studio sound systems.

Your holiday project sounds much better than mine....
Logged

Stephen Swaffer

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2370
Re: Power Outlets Worldwide;
« Reply #38 on: December 26, 2013, 02:52:38 pm »

Having brass/silver screws to determine live and neutral seems strange to me as it's the sort of thing which most people are not going to notice.

I would argue that "most" people perhaps should refrain from wiring a plug.  :).  I do not use them to determine how a plug is wired; however, if I find myself wiring a hot wire to a silver screw and a neutral wire to a brass colored screw, you can bet I am going to stop and double check my work.  Maybe its just me, but the more clues I have to help me get it right the better. To quote another post in another place "I am paranoid-but am I paranoid enough."

The devil is in the details-it is usually little things that cause big headaches in sound setups-and dangerous situations in power wiring.
Logged
Steve Swaffer

ProSoundWeb Community

Re: Power Outlets Worldwide;
« Reply #38 on: December 26, 2013, 02:52:38 pm »


Pages: 1 2 3 [4]   Go Up
 



Page created in 0.066 seconds with 25 queries.