Generator redux.... Ping Sam

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- Existential Angst
  
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posted
11 years ago

Thu, Aug 9, 2012 4:03 AM

Awl --

Some delightful surprises with the 7,000 W Black Max (Sam's club), and the Fadal -- stable like a rock!!!! As was my PC a few days earlier. The only thing that knocked out the Fadal was a vintage 13" Clausing Colchester, and that knocks out the Fadal anyway, unless I have 10 hp of rpc's going. Even the compressor (26 gal Husky, nice 'pressor) did not knock out the Fadal!!

Some 20/20 hindsight advice: More details on the black max below, but all in all, it seems to deliver, altho noisily. Holy shit.... This is going to require some serious acoustic acrobatics....

Also, altho tri-fuel conversions/kits come cheap ($180 for this unit, honda gx390 motor), monkeying around with these kits, removing carbs, etc is perhaps pushing the envelope a bit, even for a shop guy, if not familiar with all this small gas engine stuff. Plus, there appears to be delicate linkages to the voltage regular whatsit, etc.-- a pita from my initial brief sleuthing.

Generatorsales.com in Maine sells almost this exact same unit for $1600, tri-fuel ready, shipping included, no tax.. Sam's has the gasoline unit for $1,000 (near $1100, with tax, plus humping this big box...), but the conversion is going to cost about $200, or more, depending.

So really, to get it from generatorsales tri-fuel ready, tested, etc is only another net $300, and if I had it to do over again, I would have

*definitely* gone this route -- just not worth the hassle/angst in diy-mode; there's enough problems with the electrical/plumbing/exhaust logistics themselves.

Also, I would recommend an automotive-type muffler/flex. stainless hose adapter, generally cheap, with the reason being not so much for less noise (altho it might help), but moreso for the tailpipe to connect a longer exhaust hose if you are going to run this inside, or in a box, as the unit's muffler has no flange to attach to. Generatorsales might be able to kluge this up for you as well.

So here's some of the testing details.

Isolated the shop electrically, started up the 5 hp rpc.... well, let me tell you, the black max did not like DAT startup!!!! BUT, the rpc started and then ran fine, flipped in the running caps, and the fadal fired right up. Then powered up various pieces of shop equpment, with the 3 ph stuff giving the generator more welding-type blips than anything else.

The big surprise was how well the compressor (single phase) behaved, and altho it indeed made the generator grunt a bit, the fadal was STILL stable! I don't know if this is a testimony for Black Max or fadal, or both. Fortunately, I reconfigured the compressor for 240, so it's a much easier electrical load to handle for the generator, being balanced. Circular saws didn't cause a problem, nothing caused a problem except the initial startup of the rpc, and the Clausing Colchester. A 13" Enco lathe, 240 single phase, caused no problems either.

Overall, a very impressive -- albeit noisy -- 1/2 hr of testing. One thing I didn't try was my single phase miller econotig welder. That will be my next test, but I'm sure it would work up to about 1/2 max amps, altho full amps would exceed the generator capacity. This is more of a curiosity than an issue, since it's not used much, and certainly not during an outage.

The other issue is the obligatory de-rating of the unit while running on natural gas, about 10% I'm told. Hopefully that won't be a shop-breaker.

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- PrecisionmachinisT
  
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posted
11 years ago

Thu, Aug 9, 2012 4:28 PM

You probably won't see a problem unless you try and draw peak output = from the spindle for more than a couple of seconds at a time, something = that I doubt you do very often in your shop.

As a point of reference, .75 kw equals appx 1 horsepower.

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posted
11 years ago

Thu, Aug 9, 2012 5:11 PM

You probably won't see a problem unless you try and draw peak output from the spindle for more than a couple of seconds at a time, something that I doubt you do very often in your shop.

As a point of reference, .75 kw equals appx 1 horsepower. =====================================================================

I rarely get the power bar over its minimum, of 30%. Once, I think I got it up to 50%. :)

What was most impressive is the handling of the compressor, with the fadal on. That was totally unexpected. But the 5 hp rpc idler just about knocks the generator itself out! Seems startups/caps of 3 ph motors have big inrush currents. But after that it's ok.

In general, I would imagine the output of most gensets should be pure sine, by definition of spinning rotors, etc. It seems to me the much bigger problem, ito "power quality", is the voltage regulation.

Fyi, there is a company called phase perfect, that makes solid state 3 ph converters, supposedly Da Bomb, ultra pure, ultra regulated, for sensitive electronics... about $5K for a unit that cranks out, iirc, 30 amps or so, each leg. They have bigger units as well. The fadals, tho, seem very forgiving, power-wise, thank gawd.