Help! Selecting generator....

khd · Sep 14, 2004

( might cost, and I said I didn't have a clue. Just to throw out a number, I said, "$20,000." )

I think you are good to go.. if she didn't blink at 20k. I think you should be able to pick up a big standy gennt for less.. even with switchbox and install.

The one we have at work is 65Kw natural gas and an auto transfer switch. Purchase price on it w/ the switch was less than 25k plus another 10 for the electrician. 20k should be pleanty enough, as Soundguy said, to get a whole house and auto switch system with install.
 
Just keep in mind the larger you go and the more automation that goes into it the more it costs you to run and maintain. I spend 1000/yr on a service contract and last spring when the switch "relay's" (the coils that drive the switch closed and hold it open) went bad it was over 2k for parts and labor to fix it. A home is not as "mission critical" but the cost of the system isn't worth a penny if it doesn't work when you need it. It is definitely a constantly maintainable item.

Regards,
Kevin

drzmatt · Sep 14, 2004

I have a Generac generator from Home Depot. I've had good luck with it so far. I think that all of the bad press that Generac has gotten on this forum is all from one person.

ByronBob · Sep 15, 2004

It wasn't the generator which got him mad it was the customer service or lack of it which bothered him. Most people realize that humans build this stuff and we as humans are able to make mistakes. But to play the "it's the other guy's fault" stuff runaround just gets people mad.

jimgerken · Sep 15, 2004

I will let you follow all the other excellent advice on generator size. However, I will add a new twist (to this thread anyway). I had a nice Honda powered 6500 watt peak unit, and it powered my house and well just fine, not including the air conditioning (never tried it). At first when it was new, it was kinda fun to have an occasion to use it. I used it for a couple outages, and many small projects too far from a power outlet in the yard. Also used it to power electric drill and saw to help build an airplane hangar in the middle of a field with no other power. It was great. I owned it for five years. Here's the eventual problem: It sets around waiting to be used. Gasoline goes stale in the tank and carb, even if you treat and drain most of it. Oil seals eventually weep from inactivity. You must run it monthly to keep it working well, preferably under load. Even if doing this monthly excersize, it will degrade over time and require a carb and tank cleaning every couple years. And its what I call "another mouth to feed" because it is a gas engine needing routine maintenance like oil changes, etc. It bothered me to have it around eventually, so I sold it. The plan is to replace with PTO powered unit of twice its size, which I can just run with my CUT. That way, no gasoline at all, diesel lasts longer and runs cheaper, tractor engine has better torque, larger alternator and tractor combined have great rolling inertia to help start larger loads, and more advantages like it takes lees space, no leaking oil and fuel fumes. I will still need to exercise it, but that should be easy without the complication of fuel in and fuel back out, oil changes, etc. Also, I am buying this 13 Kw PTO unit for the same price I originally paid for the Honda powered 6.5 Kw unit (twice the power for the same money). My 2 cents...

aardvark · Sep 15, 2004

All this thinking about generators makes me wish I had a waterwheel. Let a river and some gravity do all the work to power the generator.

reb · Sep 15, 2004

What you say makes sense. I have thought about PTO generators, but wonder about the voltage regulation. How much does the voltage change with changes in load? A complete engine/ generator usually has some feedback to increase the fuel to the engine when the load increases, keeping the output fairly constant. Also, how does the frequency vary with load? Another consideration is whether a PTO generator will idle down when the load goes off, as most normal generators will.

jimgerken · Sep 15, 2004

I cannot answer all your questions, yet, not having owned the PTO generator. My Honda powered unit did NOT idle down with load removal. I think this is a small-set only feature. I cannot imagine what would happen if you had it at idle and the water well pump motor kicked on. Part of the frequency or voltage regulation (i am not sure which or how they are related) is the speed regulation of the engine. In the case of the tractor PTO, it is held constant with a governer, in response to changing loads (within reason). My Honda unit had the same thing basically, just like my John Deere CUT, and just like my Murray push mower. A governer changes the power setting based on the load. the Honda generator was adjustable, but it ran at that one wide open setting all the time once set. I have read that it is a good thing to ask when buying a generator: Voltage levels at no load, and full load, and ask for a description or specification of the voltage output variation when PTO speed varies by plus or minus 5%. To me, this implies that frequency will be set by PTO (engine) speed. It would be a real nice luxury to have somthing sensing the frequency and setting the engine speed based on that, dynamically. I am sure that larger (more expensive) units with dedicated attached engines have this feature. I will be content with setting throttle and monitoring the voltage and frequency with one of the Radio Shock meters which are available.

Soundguy · Sep 15, 2004

( Also, I am buying this 13 Kw PTO unit )

I had the same thoughts.

After rebuilding the carb on my B/S lawnmower engine twice in 2 years for a sticky float needle due to winter storage.. I decided I didn't want another engine. I just got the 13/12kw pto genny from northern tools. Nice unit.. looks beefy.

I have 2 posts about it in the attatchment area.

Soundguy

Soundguy · Sep 15, 2004

( have thought about PTO generators, but wonder about the voltage regulation. How much does the voltage change with changes in load? )

My pto generator has worked ok so far... with the limited test I have done with it ( smal power tools / lamp ).

I hooked it up to a vom and freq counter and it held 120vac and 60hz with or without the power tool load, which again.. a 3-10 amp load on a 12kw genny is not a valid load test for drawing a conclusion from. As I use it more.. I'll post back.

Soundguy

GoodGuy · Sep 24, 2004

How come there is no discussion about tractor PTO Generators ?? Everyone is talking stand-alone units & no one is talking PTO Driven. Is the general consensus that the stand-alone units are the way to go ??
Eric