Next message: Faure, Marin: "T&T: Four cycle vs. two cycle engines"
There seems to be some question on this subject, particularly regarding AC vs.
DC.
Both volts and amps in AC are normally measured in RMS, which means
root-mean-square, and is a value of particular importance because it has the
same power producing capabilities as would be the case in DC. This means that
you can still use Ohm's Law and the Power Law with AC. The only discrepancy is
that you must be using a purely resistive circuit load (as opposed to
inductance or capacitance). This is not as big a deal as might be supposed.
All the loads on a boat you are likely to be concerned with (lights, heaters,
etc.) will be essentially resistive, with one exception, i.e.. motors which
will be a combination of inductance and resistance. The addition of inductance
changes the phase relationship between voltage and current, and thus reduces
the resultant wattage. The current to produce a given wattage at worst case,
such as an anchor winch, would be no more than about 30% greater than with DC.
Further most AC motors are rated by current, not watts.
I could carry on, but the main thing for newcomers to electricity is that
using RMS readings (which they always are unless specified otherwise - a rare
case) can be handled the same as DC for most purposes.
By the way I'm an Electrical Engineer , graduated in 1963, and worked 40 years
at the game. Don't make it harder than it needs be.
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