Re: Newbie - Current, Voltage, Resistance, Power and Transformer theory
- From: "kell" <kellrobinson@xxxxxxxxxxxx>
- Date: 16 Oct 2006 14:45:38 -0700
hdjim69 wrote:
how can we have
this HUGE amount of "pressure" (the typical explanation of what
voltage is) and hardly any current ?
No current will flow through the power line coming over the mountain
until the people in your town start turning on lamps and air
conditioners. After all that stuff gets turned on, let's say the town
consumes a megawatt.
Using round numbers:
At 100,000 volts the town's megawatt consumption comes to ten amps.
Now, let's make the math easy and say the power line coming over the
mountain has one ohm of resistance, from end to end. You have ten amps
going through a one ohm resistor (the power line). Power dissipated in
a resistor is equal to current squared times resistance for 100 watts
of heat produced in the power line. Losing 100 watts out of a million
isn't too bad.
Now imagine they leave the same power line up but decide to put 120
volts through it so everybody can plug in directly and the power
company doesn't have to put up all those transformers on the telephone
poles... Your town will draw more than eight thousand amps through a
power line with a resistance of one ohm. You can figure out what
happens next.
.
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