"Don Foreman" wrote in message
...
On Sat, 01 Oct 2005 11:17:49 -0500, Don Foreman
wrote:

It occurred to me today (now that there's a genny in my truck) that
powering a whole house with 220 with or without transfer switch
approved by "my betters" is probably not a good approach for
practical reasons.

Most small gensets, with some exceptions, have current limit on each
110-volt phase. Given a 5 KW genny, you must use 5 KW of 220, or 2.5
KW on each 110. But there's no telling how the key loads (furnace,
freezer, fridge, a few lights, maybe a TV and/or a 'puter) would be
distributed between the two phases and certainly no guarantee that
they'd be anywhere near balanced.

12-gage drop cords w/ powerstrips solve that because then I know
exactly how loads are distributed and balanced. I'll need to make
a transfer block for the furnace if it's hardwired, but it might even
have a plug. Matter of fact, I think it does though it's been a
while since I looked at it. If it doesn't have a plug, it certainly
could have and will have.

I've had some interesting conversation about gennies with a neighbor
at the lake in the last couple of days He has a bidness rewinding
big 3phase irrigation motors, also sells and repairs gennys. That
which might be a good genny for a building contractor (Honda) may not
be a good genny for reserve power backup. He cited reasons: seen
smaller Hondas unable to pick up even a furnace motor load.

I was skeptical about that for a bit, but after some thought it is
plausible. Contractor tools mostly use series-wound universal motors
for light weight, low-end torque and often variable speed.
Universal motors don't have nearly the startup surge that induction
motors have, which is often 10X rated run current. I noted that my
4-amp freezer did not like running on 170 feet of #16 extension cord;
it overheated while trying to start and being unable to do so. #16 is
quite ample for 4 amps, but it couldn't hack the start surge. The
freezer ran great when I replaced the cord with 12-gage.

He said that Honda uses electronic voltage regulation while the Winco
just excites the field with a bridge rectifier. Elex can be designed
to do the job, but they're often used to cut cost: put an inferior
generator inside a feedback loop. That can work well as long as
things are within design parameters, but things go to hell fast when
outside the envelope. Cited example: run out of gas while under
load. Cited typical result: fried elex. New elex: $300. I
could fix the elex under normal condx, but it would be a bit tough
doing it by flashlight (even Luxeon flashlight) with no instruments
save those that are battery-powered and only a butane-powered soldern'
ahrn. Bridge rectifiers can fail too, but they're **** simple to
replace. I have several of those little brix in my goodiebox.

The genny now in my truck is a Winco, made by a company in MN that
has been making gennies since 1927. There's another MN company that
mades good gennies too, in Fridley 2 miles from me: Onan. They're
premium where cost is no object: military, industrial, marine and
RV. Well beyond my need and budget. Onan is now owned by Cummins,
has been for a few years now.

Gunner, I did note your suggestion about getting an Onan genny out of
an RV.
Some issues I had with that:
-don't know whether it has 10 hours or 1000
-don't know if it's been maintained or not
-a lot of such stuff get "sold" to the insurance company and then
"junked". Ya gotta know the RV dealer to know when and where
to go dumpsterdiving.

Roy, you can now park your worry beads on this one. The linemen of
MN will be safe from Foremanian folly not codified by my betters.



I'm using an Onan 2 cyl. gen. from an air force light cart. Military unit
and has 2000 W printed on it. Almost exactly like the 5000 W units in RV's
externally. I talked to an engineer at Onan and gave him all the spec. nos.
off the thing and he said that was a unit that was derated to 2000 W as it
may be used at a high altitude military facility. He said it would put out
4000 W all day at my elevation. But it's 120 v. only and the engine is a 24
v. system. I feed it into both sides of my dist. panel. Of course all my
220 loads are inop., but it'll run a hot plate, all the house lights and the
well pump. The forced air cooling exhaust duct is plumbed into the back wall
of the garage and keeps it nice and warm during a winter power outage.
Grunts pretty hard when the 1 horse well pump kicks on, though. A friend
that deals in these large surplus resales had two of them and told me if I'd
get one running for him, he'd give me the other one. Very easy unit to fix
and there was a parts dist. place locally. They both were very low hours,
(my engine was still tight), and had had a few parts cannibalized by the
military. Mine a fuel leak at the pump that just needed a screw tightened
and I guess that's why it was made a hangar queen.
Just recently bought a 15 KW Kohler from the town of Beech Mountain, NC
that only had 421 hours on it. Propane/LNG and a 4 cyl. air cooled
Wisconsin engine. Got struck by lightning and knocked out the voltage
regulator. That'll be my winter project. We get a lot of outages where I
live, and I'd like to have my heat pump back and my water heater.