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Messages - Jim Mc

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Thanks for the  comments, guys.  Sounds like there's been no bad experience with V belts, so that's probably what I'll do.  I agree the AX or BX belts look like a good choice...

Listeroid Engines / Any New Thinking on Most Slip-Resistant Drive Belts?
« on: November 19, 2013, 01:35:32 AM »

Looks like it's been a few years since I even thought about Listeroid stuff.  I have an 8/1 India clone - now 13  years old, and, HOLY COW, I've still not built a genset out of it...

Back when I started on this, the Poly V drive was all the rage.  As I recall, the main advantage was that it's possible to run the belt over the flywheel, thus saving the cost of a big sheave for the engine side.  But now as I troll around eBay, there's plenty of BIG Browning Sheaves that wouldn't break the bank...

I want what's going to work best, with less regard to the cost, and my main concern is belt slip.

Anybody using a  decent-sized (say 10-15") conventional 'A' or 'B' section belt sheave for the engine side of the drive?  How's it workin'?

(Note that my engine is rated at 850 rpm, so I'm not needing quite the ratio of a 600 rpm engine and I have a 6 pole and 4 pole generator available)

1200/850 = 1.41
1800/850 = 2.11

"Spin down" also lowers the power line frequency, from 60, to 50 hz  to 40 hz and the lower frequencies, as they approach DC,  start causing large current surges through wound coils.

I suppose that'd be true if the voltage didn't diminish at the same rate as the frequency.  I think it does. So, I'm not convinced there'd be large current surges...

And even if there were surges of some degree, I can't imagine what coils (transformers, motors, etc) would be destroyed by a 'spin-down' surge lasting a few seconds.

Yes, I've also read that leaving a load on a generator as it spins down can destroy residual magnetism, requiring a re-flash.  I guess I'm inclined to see value in an under-freq or under-voltage lock out - mainly to disconnect the load if the engine can't maintain 60Hz for extended periods.  THAT can certainly cook induction motors, and transformers.  But I don't see how 'spin-down' is going to kill anything other than residual magnetism...

...well, really, it's a "failsafe" to keep engine failures from killing my generator and my household appliances as the system spins down.)...

Just curious, how does this spin-down effect kill generators and household appliances?  How big a generator are you talking about?

Generators / Re: Tie in an induction head and synchronous head
« on: March 10, 2010, 02:36:35 AM »
What are the potential pitfalls?

In a nutshell; the economics of selling power back  to the utility.

Lister Based Generators / Re: Speed/Governor Issues
« on: February 18, 2010, 03:49:05 AM »
OK, well  step 1 is to get the governor holding the speed as constant as possible in going from full to no-load.  The longer, weaker spring will help.

Then recognize that the frequency is dependent on the speed, and on nothing else.

So if you have 5% speed droop,  you'll have 5% frequency droop.  It's that simple.

Voltage is a slightly different story, but with an ST head and no AVR, you're pretty much stuck with whatever it provides.  The voltage depends on the speed to a degree, and also on the load.  Bottom line is you may see some improvement from governor tweaks, but you'll probably be fine with voltage in the 120-130 range and frequency in the 58-62 Hz range...

What's your most sensitive load?

Lister Based Generators / Re: Speed/Governor Issues
« on: February 18, 2010, 02:54:52 AM »
How did you decrease the voltage to 120? 

And exactly what problem are you trying to fix?  the too-high no-load voltage?  The drop in frequency?  The drop in voltage?

Lister Based Generators / Re: Speed/Governor Issues
« on: February 17, 2010, 02:50:13 AM »
Anyone have any suggestions for keeping the rpm of the engine constant at 650 so that my gen spits out 60hz? .


The basic tweak is to remove the original governor spring and replace it with a longer, weaker spring.  You'll need to modify the fixed point mount by moving it away from the governor to allow the spring to be stretched to a greater length. 

Very simple.  Very effective.

General Discussion / Re: Global warming ?
« on: December 15, 2009, 12:54:52 AM »
Ahh yes, majority rules.  If enough people think it's real, never mind real science...

General Discussion / Re: Climate Warming a hoax?
« on: December 15, 2009, 12:50:49 AM »
Top notch stuff, T19.  What do you think, Stan?

General Discussion / Re: Climate Warming a hoax?
« on: December 14, 2009, 03:27:36 PM »
^^ I guess that means 'no'?

In other words, you have no further defense of your experiment?

General Discussion / Re: Climate Warming a hoax?
« on: December 14, 2009, 01:35:08 AM »
Does he explain your experiment?

General Discussion / Re: Climate Warming a hoax?
« on: December 13, 2009, 04:53:52 PM »
You should really read up on the physics of sunlight and how it heats the earth...

I have.  How about you? ;D

General Discussion / Re: Climate Warming a hoax?
« on: December 10, 2009, 12:00:32 AM »
Jim, the earth doesn't lose heat exclusively through radiation to space. 

Yes, it does.

... carries the heat waaay up into the sky and then it radiates out into space. 

 Exactly.  All the heat the earth loses is lost by radiation to space.  No other way for heat to escape our earth/atmosphere system.  Convection does carry it 'waaay' up into the atmoshere, but then what?  It has to be radiated out to space - convection stops when there's no more atmosphere.

...just like my box loses heat into the "space" of the classroom.

No, not like your box.  As I stated, earth's heat is lost by radiation, your box loses it by other means.

Your box is a very poor model...  And the results of your experiment should not be extrapolated to earth. To continue to do so is misleading your students.

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