Can anyone tell me please tell me the difference in electric consumption between a low-voltage AC circuit containing three, 35-W bulbs on a 12-Volt AC circuit as opposed to the same circuit operating at regular household current of 115V?? I assume it is less on the
12V??? Thank you very much."Tony" wrote in news:1169676266.575825.307060 @k78g2000cwa.googlegroups.com:
35 Watts from a 12 volt system is the same as 35 Watts from a 115 volt system, one uses less current...----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
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But if it's the lamps that are rated 35 W, the 115 VAC circuit uses more power because the conversion from 115 VAC to 35 V isn't 100 percent efficient. :)
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Sam Goldwasser wrote in news: snipped-for-privacy@plus.seas.upenn.edu:
I take it you mean the 12 V system uses more because the losses in thransforming from 115 V. (?) Then sure the low voltage system will use slightly more, but the original question really didn't appear to need finer technical detail.
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It is a case of comparing apples with apples....
Both the 115Vac and 12Vac lamps consume a total of 105W if we assume that the same lamp technology is used. However, there may be a considerable difference in the light output from both lamps even though the power consumption is the same. Also, because the transformer or electronic ballast, which converts the 115Vac to 12Vac is not 100% efficient, some loss will occur in this device. Therefore, some additional power will be consumed in this device for the 12Vac lamp arrangement.
A 12Vac halogen lamp will produce a higher light output at lower power consumption than a 115Vac tungsten filament lamp having the same wattage rating. For the 115Vac tungsten lamp to produce an equivalent light output to the 12Vac halogen lamp it would have to consume more power and it would thus have a higher wattage rating because it is relatively inefficient at converting energy to light.
It all comes down to the efficiency of converting AC power into light output, and of course personal preferences and economics. Converting house lighting from tungsten filament lamps to 12Vac halogen can be more efficient in energy consumption but it also depends to some extent on aesthetics and whether the light pattern produced is suitable for the intended living area. Halogen lighting generally tends to be more "beamed or focussed" so to fill a room with even light may require more 12Vac lamps than for a system using say tungsten filament or high efficiency flouro lamps, which means you end up using a similar amount of power to produce that even lighting.
Horses for courses...
Watts are watts, the current will be much lower on the 120V circuit but the consumption will be identical.
Nope, slightly more. There are various losses involved in running from 12 V.
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So, I can assume it would be cheaper in terms of KWH to operate the
12VAC system than the 115VAC? Is this correct please? Thankxon the 120V circuit but
Hi...
Yes, in pure theory. A power transformer is about the most efficient thing there is, so in practical terms the effect would be virtually nil.
Suggest you make your decision on which to use based on other factors.
12 volts is much safer than 120 volts. Cost of bulbs? Don't know where you are, but in some places an electrician is required to run 120, but you can do 12 yourself. Location of transformer if you go that way - there's a slight possibility it may hum a bit. (like the isolation transformer shaver outlet in my bathroom... durned thing :(There are more considerations. In or near a swimming pool? Hot tub?
Take care.
Ken
"Ken Weitzel" wrote in message news:n2buh.785813$5R2.264143@pd7urf3no...
But the current is higher so the wiring losses are as well. That's why most countries went with 220 - 240 volts and not the Edison 100 volt system.
"Edison's DC distribution system consisted of generating plants feeding heavy distribution conductors, with customer loads (lighting and motors) tapped off it. The system operated at the same voltage level throughout; for example, 100 volt lamps at the customer's location would be connected to a generator supplying 110 volts, to allow for some voltage drop in the wires between the generator and load. The voltage level was chosen for convenience in lamp manufacture; and at the time it was felt that 100 volts was not likely to present a severe hazard of electrocution. To economize on the cost of copper conductors, a three-wire distribution system was used. In the Edison system, the three wires were at +110 volts, 0 volts and -110 volts relative potential. 100-volt lamps could be operated between either the +110 or -110 volt legs of the system and the 0-volt "neutral" conductor, which only carried the unbalanced current between the + and - sources. The resulting three-wire system used less copper wire for a given quantity of electric power transmitted, while still maintaining (relatively) low voltages. However, even with this innovation, the voltage drop due to the resistance of the system conductors was so high that generating plants had to be located within a mile (1.6km) or so of the load, otherwise very large expensive conductors would be needed or else very high voltage drops (and efficiency losses) would result."
Nope. You are better off using CFL off 115 for lighting in my experience. There is no cheaper source of power than the stuff the electric co sells.
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