Re: [CAD_CAM_EDM_DRO] Re Power Supply

On Friday 16 December 2005 01:17 pm, Blue wrote:

> Contrary to popular belief electricity generation by alternator is not free
> and the laws of physics still apply i.e. power in = less power out.

A good point, and one that came to me after I'd sent my last post on the
subject...

> I doubt few lathe users on this list have machines large enough to drive an
> alternator never mind two.

You don't need two.

> You will notice a huge reduction in mileage during the winter months because
> of heaters, rear window heaters, wipers and more use of lights. In fact
> anything up to 10% of a cars power can disappear by generating electricity
> for normal use, I shudder to think how much fuel is used running the boom
> boxes the young like to deafen themselves with.

Those setups need a heavier-duty alternator than the stock model, and often
need a separate battery to run it as well. And I've seen some folks cook
_those_ completely dry (back when I was in the retail battery business).

> There are also other considerations other than the required power.
> Alternators are 3 phase machines containing 9 diodes, which rely on having
> a battery and voltage regulation to pad the system. I've had more than 50
> volts from them but the usual voltage for charging the cars electrical
> system is 14.4 volts.

Yes. Some sort of regulator is going to be necessary, for sure. Oh, and
BTW, I understand that some of the newer GM stuff uses more phases than
that, a whole lot more.

Sizing a capacitor for this is going to be troublesome, too, because the
frequency of the output is going to depend on the speed that you're driving
it at.

--
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ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
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