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Backup Generater
bj:
The motivation to build a gen-set was really water. Water doesn't move here
without power, and when it gets to -40 C, no power is almost a guarantee. Most
of the time it is line breakage, and that is usually a 5 to 6 hour repair.
Heat is a secondary issue, as we have natural gas, and a natural gas fire-place
( 30,000 BTU). I built the house with lots of insulation. So, 6 hours is not that
much of a hardship.
And then, of course is the coffee. (might be higher on the list)
The engine I chose for the gen-set was a 12.5 Briggs, that had mega-hours on it. Too big an engine for the purpose, but I like overkill, and it was a vertical shaft.
This was important, for space considerations.
The motor still ran O.K., but used a bit of oil. So, a total overhaul was in order.
The alternator took a bit of time, waiting for it to go on sale. Patience finally
won out, and a 4kw (5kw peak) belt drive was mine. I could have used a belt on it, but opted for a large Love-joy style coupling for simplicity. The alternator was designed to
be Bi-directional, so that wasn't an issue.
I made the stand from a selection of steel that was in my “not quite scrap” bin.
The motor base plate was 1/2 inch steel, so I could tap in any attachment holes.
The legs (4) are 3/4 inch schedule 40, and the floor plate is 1/4 inch.
I spent more than a bit of time getting the alignment dead on, making battery
mounts, and getting the 12V system as bullet proof as I could.
The whole thing sits on a sheet of 1/4 neoprene, with shock rubbers on the
mounting bolts.
Once I got it all assembled, a test run pointed out a serious flaw. Noise.
The 12.5 has a seriously loud exhaust. After much messing around I settled
on two older style Acura mufflers in series. This combined with the 10 feet of exhaust
piping to get out the wall, made for an acceptable noise level.
A try-out, with shop and house furnaces maxed, a bunch of lights on, and
most importantly the coffee pot on, showed that the motor is lots big enough,
and the alternator runs at slightly warmer than skin temp. All was good for about
two hours, then I noticed a change in engine tone. Not rpm, just tone. The frequency
was holding at 59.9 hz., but the voltage was dropping. A quick run to the shop to
throw the breaker for the air compressor solved it. (lesson for future)
All in all, for a total cost of $490, and some work, a success. Of course, now
that it's done, there probably wont' be any power failures longer than 10 minutes.
ChrisOlson:
bj, I think I seen that before someplace. But that setup is just plain NICE!
Does it have electric start? I think I got a starter laying around my shop for one of those Briggs 12.5 I/C engines.
--
Chris
WooferHound:
The best way to prevent a power failure is to prepare for one.
I was fortunate to have a Solar power system that was working wonderfully when we had tornadoes in April 2011. The power was off for 5 1/2 days and the Sun was beaming plenty too. So this year I have bought new batteries and some stuff that I needed at the time of the last outage.
So now I can guarantee anybody in the North Alabama area that there will be no significant power failures in the near future.
Are you recovering any heat from the exhaust ?
Watt:
--- Quote from: ChrisOlson on February 03, 2012, 06:08:40 pm ---bj, I think I seen that before someplace. But that setup is just plain NICE!
Does it have electric start? I think I got a starter laying around my shop for one of those Briggs 12.5 I/C engines.
--
Chris
--- End quote ---
I agree, nice job.
Must be electric, I don't see a rope.
ChrisOlson:
--- Quote from: Watt on February 03, 2012, 06:25:14 pm ---Must be electric, I don't see a rope.
--- End quote ---
I couldn't tell for sure. It looks like it might have one of those wrap-the-rope-around-the-spool outfits on the top of the air screen on the flywheel.
--
Chris
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