> Being an RV"er (and a MGB loyalist), I have never heard of an Electric A/C
> system used in in a vehicule. The A/C system seen on top of RV"s are 120
>Volts
> operated when stationnary.
> If an engine driven A/C system requires say 4HP to run a compressor, the same
> 4HP (electric power) would be required. This would require a fairly large
> electric Motor with a very large amp demand. I do not think any current 12V
> system could take this for very long. If my calculations are right (I know
> there are electrical engineers around that could (and will, if I goofed)
> destroy my theory) such an electric motor would require 350 Amps to start
>and
> about 125 amps to run. Not many alternator can sustain that output for long.
> JDMG@msn.com
> Jacques
> "74 B (Chrome) no A/C but top down year round
>
Jacques,
My numbers work out a little different, but much to the same
conclusion. If 4 hp is a good number for the compressor rating, this
is just under 3000 watts (1hp=746 watts). Let's call it 3000 watts.
For a twelve-volt system, this would require about 250 amps.
(3000 watts/12V). This is assuming the motor would be 100%
efficient, which it almost certainly wouldn't be. So unless some
kind of inverter/transformer setup is involved to raise the voltge
and drop the amps, I must have had the wrong idea about what actually
powers the Rover's compressor.
Scott
Scott Gardner
gardner@lwcomm.com
www.lwcomm.com/~gardner
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