David Lesher wrote:
Winston writes:

?Short? I do agree that current limiting will be a major issue.

228 A through a 50 A alternator. Until a real short shows up,
this will do nicely.

So your portable one-lung generator will source 228 amps? At 120V that
means 27 KW. The small portable gas generator in my garage is a lowly
0.75 KW; I'm jealous..

The generator is an unknown. Is it a 6 cyl. diesel behind the cabin
or a nice little Honda inverter?

All we know is that our intrepid cabin builder will get nowhere fast
by connecting it to the truck without any current limiting.
The generator is not going to 'grunt and supply'. It will
fail safe or short out or it will take out the alternator and attached
wiring. None of these options will get our guy back on the road and
to dinner.

One issue on the drill is while its nominal reactance is well suited for
our needs; it will draw a lot more in locked rotor mode. If it does not
quickly get out of that mode and to a reasonable RPM, will it still
be a suitable current limit....?

It will be out of 'locked rotor' mode very quickly.
As you point out, these drills use phase modulation to control speed.
I figure that 90% of half wave should spin the drill at about 40%
of maximum RPM with no mechanical load. That'll do and it'll charge
our guy's truck battery at a fast, yet safe rate.

(...)

Or one could look at the drill motor nameplate and subtract ~60%.

Lamp is at least resistive, and linear over the DCish waveform.

I didn't see a lamp in the inventory. A headlamp will have
only 10% of the resistance we need anyway.

I am embarrassed for not suggesting that our intrepid cabin builder
just swap out his battery for the charged one in the back of
his truck. If you can materialize objects into the scenario, I can
too, right?

MR. SPOCK: Say again, captain? You want me to beam down
a *truck battery*?

CAPT. KIRK: Yes and don't suggest that I should mine some
lead and begin looking for some lemons.



--Winston



--

Don't *faff*, dear.