| Mark Henry |
08-06-2012 11:59 AM |
Quote:
Originally Posted by 1990C4S
(Post 6896752)
False. E=IR. You can double the voltage and cut the current in half. The power consumption is unchanged. There is no free lunch, aside from running the device on a smaller conductor at the higher voltage.
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This is the reason you do this, increasing volts and reducing amps is safer, evens out the load and the equipment will last longer.
Quote:
beepbeep
This is nice, although our outlet fuses are usually in 10A-16A range. My whole house is secured by three 25A-fuses. MY understanding is that US households have larger fuses?
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Old homes have 60amp services if they haven't been upgraded, small homes will have 100amps, larger homes will have a 200amp service, some real large homes have a 400amp service.
My house (and 2-car garage) has a 200amp service, that also feeds my shops 100amp service.
Quote:
rick-l
In the US most homes have a split phase 3 wire power system. It is a transformer with a center tap. Across both windings you get 240 across either one you get 120. The three phases (the way the power is generated) is split between neighborhoods with one phase high voltage powering these transformers on the pole.
This system dates back to Thomas Edison when he was trying to reduce distribution costs for DC lamps with carbon filaments that needed 100 volts DC. (P = V I so twice the voltage requires half the current for the same power) Westinghouse followed this design with AC.
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3 phase AC is from Tesla, Edison's system used lower voltage (at the time, right or wrong, deemed safer) and the current system is a compromise between the two. In the 50's there was talk about a world standard (3 phase) but North America already had so many households with 110 appliances (where Europe did not, as it was behind because it was still in recovery mode from the war) that the idea was scraped.
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