USA converting back to Direct Current

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boater bill

Senior Member
so maybe this thread should be renamed "US Not Convertig back to Direct Current"
That's what I said early on.

the idea of an Energy Star home on solar is admirable, but expensive and impracticle unless it is remote and not serviced by the utility grid.
 

Rampage_Rick

Senior Member
tom baker said:
A question came up on why we don't use DC for traffic signal cabinets, as most signal heads are DC leds. The answer was there is a significant corrosion issue with DC, and there is a voltage drop issue that you don't have with AC.
But if you had LEDs would you not end up only using half the AC waveform? In theory you'd only have current flowing one direction, though one head might be hot > neutral and another might be neutral > hot.

Of course now someone is going to tell me that LED signal heads employ bridge rectifiers to avoid this issue.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Rampage_Rick said:
Of course now someone is going to tell me that LED signal heads employ bridge rectifiers to avoid this issue.
Either that, or front-to-back pairs.
 

No Show

Member
No Show said:
This link talks about a city in NY(I believe to be Buffalo) that has been supplied with direct current for 125 years, how did they deal with corrosion? Also alot of you are only considering PV as the sole sourse, wind energy will charge a system when the it cloudy or at night when the sun may not. Also consider natural capacitors, thermal, hydro, what if every time you flushed the toliet,or took a shower you were generating electricity. I think that one day in the very near future it will all come together and be reality a system that is is independant even if it uses the grid as a form of redundancy, AC or DC or both
 

dereckbc

Moderator
Staff member
No Show said:
This link talks about a city in NY(I believe to be Buffalo) that has been supplied with direct current for 125 years,
It was Parts of Manhattan on the very old Con Edison system, and it is all gone as of Nov 17. The convesion, or elimination started in 1928, it was predicted it would take 45 years to eliminate DC, it took longer, but there is no going back.
 

No Show

Member
I hooked up a semulator one time at the German Air Force Base in Texas and I had to use a rectifier cause it was 240v DC and I was under the empression that most of europe was operating on DC. If so how and why?
 

dereckbc

Moderator
Staff member
No Europe uses 240 VAC @ 50 Hz. No country uses DC to my knowledge. Only place DC was ever used was around NYC when Edison built the first commercial power grid, and it was completly disconnected last month.

Not sure why an aircraft would use 240 VDC as most aircraft use either 28 VDC or 400 HZ AC. My guess is some odd German design. Not a military guy so I don't really know.

Here is a link with all the voltages used globally:
http://www.kropla.com/electric2.htm
 
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kc8dxx

Senior Member
dereckbc said:
No Europe uses 240 VAC @ 50 Hz. No country uses DC to my knowledge. Only place DC was ever used was around NYC when Edison built the first commercial power grid, and it was completly disconnected last month.

Not sure why an aircraft would use 240 VDC as most aircraft use either 28 VDC or 400 HZ AC. My guess is some odd German design. Not a military guy so I don't really know.

Here is a link with all the voltages used globally:
http://www.kropla.com/electric2.htm
270 VDC is available in some military and prototype commercial aircraft systems.
 

Energy-Miser

Senior Member
dereckbc said:
No Europe uses 240 VAC @ 50 Hz. No country uses DC to my knowledge. Only place DC was ever used was around NYC when Edison built the first commercial power grid, and it was completly disconnected last month.

Not sure why an aircraft would use 240 VDC as most aircraft use either 28 VDC or 400 HZ AC. My guess is some odd German design. Not a military guy so I don't really know.

Here is a link with all the voltages used globally:
http://www.kropla.com/electric2.htm
Thanks very useful link. For all who visit this link, be sure to check out the plug types. It is intersting how many different configurations there are. One in particular (type E), has a male receptacle pin for the its EG connection, never seen that before. e/m
 

Energy-Miser

Senior Member
Rampage_Rick said:
...
Of course now someone is going to tell me that LED signal heads employ bridge rectifiers to avoid this issue.
LED signal heads employ bridge rectifiers to avoid this issue :) e/m
 

No Show

Member
dereckbc said:
No Europe uses 240 VAC @ 50 Hz. No country uses DC to my knowledge. Only place DC was ever used was around NYC when Edison built the first commercial power grid, and it was completly disconnected last month.

Not sure why an aircraft would use 240 VDC as most aircraft use either 28 VDC or 400 HZ AC. My guess is some odd German design. Not a military guy so I don't really know.
It must have been some type of an inverter that only changed the hertz from 60 to 50 then. :smile: Thanks
 
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boater bill

Senior Member
Works for me.

BTW, here is a link to a solar power contractor in my area that has a ton of info and links for homes off of the grid. All of the appliances are AC.

http://www.keypowerservices.com/

This discussion reminded of the SAE to metric discussions of the 80's, it sounded great on paper but no one was going to pay to replace all of their machine tools without a return for their investment.
 
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