Old Iron (engine generator)

Right after the Cuban missle crisis, the Civil Defense chartered the building of "community bomb shelters". The locals had to raise the money for the construction and infrastructure. CD stocked them, gave training, coordinated drills, etc.

We had one in DeLeon Springs (Fl) that was finished in 1962. That year, CD put a spankin' new Dayton 3.5KW genset in the below-ground shelter, and locked the doors.

In 1974, my dad and I were hired to clean out all government-owned items, "de-mil" them, and weld the doors shut on the abandoned concrete tomb. We pulled out the old genny, which had been sitting on wet concrete for 12 years. It was a fur ball of rust, but what the hey... it still looked like some good iron.

It sat in a (dry) warehouse until 1988, when I dragged it out and began a tear-down. After getting the whole thing down to nuts, it was apparent that really nothing was wrong except the magneto coil was shorted and the carburetor bowl and venturi area was corroded to ruin.

The old 10HP cast iron updraft Briggs still had compression. The genny slip rings were corroded, but we polished them. A replacement pull-off carb and an automotive style coil got the thing running after only about a day of work, in toto. (the genny has a 12vdc battery charger output, so that runs the coil after it's started)

Every summer, I fire it up, just to make sure. We have storms here. I always only plug in about the maximum load I expect to run -- in my case one half-horse water pump and about 1000watts of incandescent lights. And it always pulls the load.

This spring, I "decommissioned" our old central AC, and saved a few components; relays, caps, etc. For whatever reason, I also saved the heat-strip insert -- a 230V, 4800watt resistance heater.

Last night, I fired up the genny for a warmup, because the remants of Ernesto were headed for us. This time, I plugged the heat strips in for a test load. My expectation was that the field would quench, but I wanted to see, anyway.

Damned if the 44 year old Dayton didn't just lean into that load like a mule to a plow! It RAN the coil, and the output only dropped to about 205v! Daggone! It's just a 3500 watt unit!

Let's see one of the new "peak rated" gennies do THAT!

I LOVE old iron!

LLoyd

Reply to
Lloyd E. Sponenburgh
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So do I. The good old times, when things were "conservatively rated".

i
Reply to
Ignoramus20617

Reply to
RoyJ

Gentle, yes; as in, "no inrush" (to speak of). No... it didn't "bog down". The engine never sagged, the voltage did, because of internal resistance in the windings.

At 205V, the heater never got up to as high a temp as it would have at 230v, so it actually drew more current. The 4.8Kw load was probably real.

LLoyd

Reply to
Lloyd E. Sponenburgh

Would be good to find out what happened to the frequency.

Did you hear that the motor ran any differently?

i
Reply to
Ignoramus20617

Built in a day when manufacturers and advertisers still had a conscience, and consumers still knew what RMS meant, vs. peak. In our uneducated ignorance they can now tell us all sorts of crap and we swallow it. I have here a Ridgid shop vac, 110V, labelled as 3.5 peak hp. As if it could sustain that beyond the first 25 milliseconds at startup. Same goes for the Sears compressors. And I suspect it also goes for a lot of current automobiles... And built in a day when they made things better just so they would last a long time and give the company a good reputation for the future. We seem to have much shorter memories now, and keep buying substandard stuff.

Dan

Reply to
Dan_Thomas_nospam

I have a "5 HP" 110V vacuum. (a scam rating, obviously).

Some guy on our local craigslist keeps trying to sell a "5 HP" 110v compressor.

You mean coming to a screeching halt, right?

I think that anything over-rated, is usually marketed to idiots and, thusly, very poorly built.

i
Reply to
Ignoramus20617

It lost maybe 3% (by ear) RPM... didn't lug at all.

LLoyd

Reply to
Lloyd E. Sponenburgh

Reply to
RoyJ

This one glows bright red, even at the 205V input; it's incandescent orange at 230V.

The resistance should change substantially. But no; I didn't meter it.

LLoyd

Reply to
Lloyd E. Sponenburgh

And it's rated at 4800 at 230V for a power use of 4278 at 205V, even if there were no change.

LLoyd

Reply to
Lloyd E. Sponenburgh

Yeah, ever since Sears got involved, watts seem to have shrunk down a bit.

I bet your genrator is an 1800 rpm unit as well. Those are nice.

Jim

Reply to
jim rozen

Another old iron fan here!

By the way, talking about misleading marketing, did anyone ever understand the term "watts PMPO" and its relationship to watts RMS when talking about speakers?

Chris

Reply to
Christopher Tidy

Sure. Hook up some 4 ohm speakers, crank up the volume to eleven, play a snare drum hit, measure the peak voltage across the speaker, square it and divide by 4. Peak music power. At some point, the mid-level amp builders would quote the peak music power at some large level of distortion, which would mean turning the amp to nine instead of eleven (:

The relationship to RMS would be highly dependent on the size of the power supply filter caps and the current rating of the power transformer.

For a quality amp, I would suspect that the RMS rating would be the intuitive value of peak * .707, at least until thermal issues started to appear. For the cheap amps, all bets are off.

Reply to
Jim Stewart

Hmmm. Thanks. Sounds about as misleading as I expected!

Chris

Reply to
Christopher Tidy

You want misleading, look at car audio head-ends and power amps. They quote huge RMS Wattage ratings, but they curiously fail to mention the % of Total Harmonic Distortion at that power output rating. Which is usually buried in the fine print on the back of the box and is something ridiculous like 20% or higher.

Some tone-deaf people couldn't hear or discern a 20% THD if you gave them an A/B test with a clean source to compare it to...

But those of us with very good hearing will hear it and literally get driven out of the room (fingernails on a chalkboard) at far lower distortion levels - under 1%

And we also hear the flyback transformers on CRT TV's and monitors, but after a few decades you learn to tune them out.

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Reply to
Bruce L. Bergman

My "small-sounds" hearing is spooky sometimes even to me. An example: A big ol' Dodge RAM with the Cummins diesel is idling near where I'm dealing with I-forget-what-it-was-now - I think I was putting together a new hay-bunker for a new horse at the stable as its headlights provided the means for me to see to do it. Partway through the task I notice a sound... A wrong sound. A teensy-tiny little sound. A repeating sound on about a 1.5 second interval. A sound a lot like water dripping. I can't pin down its exact location due to the noise of the truck engine, but it seems to be strongest when I'm pointed toward the truck. And it's starting to drive me nutso.

"Hey, Justin - I think your truck's bleeding."

Justin: "Huh, wuddaya mean?"

"I hear something dripping."

Justin: "Are you stoned??? You can't hear anything dripping over this motor running! Come on, hurry up so we can get back to the bunkhouse and out of this heat!" (This was during a string of almost 3 weeks where the temperature didn't go below 117 F day or night.)

"I'm telling you, you've got a leak in that thing somewhere."

J: "I'll be damned - Water pump is leaking a little. How'd you hear that?!?"

"Uhh... damned if I know, but it was starting to drive me nuts."

His water pump let go completely the next afternoon.

Reply to
Don Bruder

And people drop change on concrete and you can tell what it is by the note, and follow which way it bounced by tracking it. Dime... Penny... Quarter... 8/32 Wingnut - How'd that get in there?

Great diagnostic equipment once you learn to use it.

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Reply to
Bruce L. Bergman

I was pondering this a couple of days ago when I saw an ad for a 1000 watt amp. Simple ohm's law says you'd need 32 volts across a 1 ohm speaker to produce 1000 watts. So do they parallel multiple speakers to get an even lower impedance for the amp or what?

Reply to
Jim Stewart

Okay, so I'm late and catching up, but Gunner wrote on Fri, 01 Sep 2006 17:02:38 GMT in rec.crafts.metalworking :

"Ah, it was so quiet, you could hear a pin drop. A bowling pin!"

pyotr

Thank you, thank you. I'll be here all week, tell your friends.

-- pyotr filipivich We will drink no whiskey before its nine. It's eight fifty eight. Close enough!

Reply to
phamp

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