Author Topic: 350 rpm 6/1?  (Read 14753 times)

650rpm

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350 rpm 6/1?
« on: July 30, 2015, 11:31:41 PM »
I remember a while back there was a lot of talk about running the 6/1 at 350rpm. Im having trouble finding any of those threads. Just wondering if anyone reading this runs their engines this slow and what their experiences have been as far as governor control and proper oiling. I bought a 4.2 inch pulley for my St-5 just to try it out (although I checked my math after and realized I should have bought a 5"). I thought for a lot of my use Im just charging my house batteries and running a few small loads and running full speed just for that seemed overkill.

38ac

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Re: 350 rpm 6/1?
« Reply #1 on: July 31, 2015, 12:10:48 PM »
I don't think there is much real life dope on that subject but lots of opinions and theory, which is fine as long as each is properly represented.  I have no long hour data but I have owned a few CS types that were "show" engines and thus I had them slowed down quite a bit. After reading about lubrication problems (that I had not thought about) I removed the crankcase door from one of them that had sat a long time just to verify what it looked like inside and then replaced the door. I started the engine, ran it for a minute then shut it down. As I remember this was around your RPM spec. When I removed the door I was totally satisfied that nothing was starving for oil for my use which was powering nothing.  You can preform that simple test yourself.

Variables here are of course the loading. Another one is the type of internals you are dealing with. Remember I was dealing with a real CS, thus an oil pump and a dipper, bushing mains, and a shelf type sump. You get a lot of oil thrown from the crankshaft when your pumping oil to the mains that you don't have on a pumpless engine. On a 'roid you could turn the dipper sideways for more splash or even make up a custom one that would drown things in oil even at 100 RPM if you so wished.

Governor control at low RPMs is going to get funky no matter what you do because the camshaft is only going to be turning 175RPM at your spec. Control will always be improved by using the lightest and longest spring that will give the required RPM. In your case the weights might need to be lightened also. I wouldn't do that as a first step ,but the last one after many springs were tried.

Butch
« Last Edit: July 31, 2015, 12:15:49 PM by 38ac »
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BruceM

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Re: 350 rpm 6/1?
« Reply #2 on: July 31, 2015, 02:17:06 PM »
AC generator head voltage/frequency variation at the 350 RPM - 5 Hz power stroke would be quite bad and problematic for some equipment.  An AVR which is responsive enough (units with analog RMS voltage regulation are not) should help with voltage, but during compression there will still be a substantial frequency (and likely voltage) sag.  The SOM flywheels would help some, but at 350 rpm, I'd be thinking more along the lines of DC generation, with battery/inverter for AC.  It's would certainly be worth experimenting (please post about it!), but keep a very close eye/ear on your equipment under test and stop if heating/vibration/etc. appear significant.

I think Butch meant adding weight to the counterweights for 350rpm.


38ac

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Re: 350 rpm 6/1?
« Reply #3 on: August 01, 2015, 02:08:13 AM »
Uh, good thing I have smart people watching closely. Bruce is of course correct, you would add weight the governor l.
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650rpm

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Re: 350 rpm 6/1?
« Reply #4 on: August 01, 2015, 10:12:51 PM »
Well my test with the 4.2" pulley lasted only a couple seconds so far with the unexpected: My St5 started to jump in its track. Two things: One I think I need a shorted belt and keep the head as close to the engine as possible, and two, the weight and circumference of the 8.5" kept it in balance. My St5 just sits in a sliding track and is held down only by its weight. This also means that there is a lot of side pull on the heads bearings when the head is farther from the engine. Going in to town in a few days to get a shorter belt and get some softer springs, and see what happens :)

Thank you for the feedback and advice! Yes I like the DC charging idea. Would be fun to built an Axial Flux alternator.

M61hops

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Re: 350 rpm 6/1?
« Reply #5 on: August 04, 2015, 10:12:37 AM »
Hi 650rpm.  I like to re-purpose auto parts to use for Listeroid projects.  I'd get an alternator from a truck or car that has a ribbed pulley already on it and charge batteries direct.  You don't have power pulse problems that way!
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cornwallav8r

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Re: 350 rpm 6/1?
« Reply #6 on: August 04, 2015, 07:45:54 PM »
I like the idea of using a large inverter and possibly a buffer battery or large capacitor. You can rectify your AC output or just make DC. A few percent of losses, but it allows your prime mover governor to be sloppy as it wants and still do the job.

650rpm

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Re: 350 rpm 6/1?
« Reply #7 on: August 04, 2015, 09:55:30 PM »
The Iota series battery chargers were designed intentionally to handle poor generator input. "Power factor correction" it takes in 107V to 132V and 50 to 63 hz so Im sure there would be losses going from AC to DC especially since the charger uses much more power than it outputs for some reason, but it would work...I do have a 55amp delco alternator, I just need to figure out at mount, but the problem is the engine is like 50 feet from the solar/battery setup, so long large guage wires...

Im still waiting for my drive belt from RockAuto tomorrow, but I ran the engine for a while at 350rpm. The governor varied about 10 HP no load  (which is actally better than at 688 rpm) and after I looked inside and everything looked coated in oil well.

Is there a way to calculate the power output at various rpms? Is it as simple as 650 expect 3KW and 350 around 1500?

BruceM

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Re: 350 rpm 6/1?
« Reply #8 on: August 05, 2015, 02:43:45 PM »
Yes, reducing a CS type engine speed in half should give you roughly half the hp.  It does depend on the torque curve for the engine, and I've not seen that characterized for the CS types.


mike90045

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Re: 350 rpm 6/1?
« Reply #9 on: August 05, 2015, 11:53:55 PM »
The Iota series battery chargers were designed intentionally to handle poor generator input. "Power factor correction" it takes in 107V to 132V and 50 to 63 hz so Im sure there would be losses going from AC to DC especially since the charger uses much more power than it outputs for some reason,....

That reason is the Iota chargers have poor PF (power factor)   I would not recommend using one, if you can find something else. Has nothing to do with being designed for generators.

Quinnf

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Re: 350 rpm 6/1?
« Reply #10 on: August 07, 2015, 01:55:47 AM »
Speaking theoretically, the engine was designed to run at 650 rpm.  The flywheel weight and governor weight and geometry were optimized for that speed.  The flywheel's kinetic energy is a function of the square of the speed of the flywheel.  So if you reduce the speed by half, the energy stored in the flywheel is only 1/4 what it was at 650 rpm.  I'd be concerned about the effect on the rod bearings and the crankshaft.  Running an engine at a show with no load at half speed is no problem, but if you're making it work, the engine will very soon be lugging.  I'm not sure that's a good idea.  Again, speaking theoretically. 

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Thob

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Re: 350 rpm 6/1?
« Reply #11 on: August 07, 2015, 02:54:24 AM »
At some point, slowing the engine down actually hurts the fuel economy.  It gets to the point where you have a lot of time for gas to blow past the rings, and you loose power and efficiency.  Unfortunately, I don't know what that RPM is - but if you're going to do this it would worth doing a fuel consumption test at 650 and another at 350.  Maybe one at 500 RPM?
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veggie

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Re: 350 rpm 6/1?
« Reply #12 on: September 14, 2015, 11:58:13 PM »
There are many examples of users running listeroids between 350 and 500 rpm.

Here are just a few:

This one at 450 rpm..
https://www.youtube.com/watch?v=vl8zn7Lf-lQ&feature=mfu_in_order&list=UL

This one is running at 340 rpm...
https://www.youtube.com/watch?v=w3xYh0VJE78

Here is a "working" listeroid at 370 rpm
https://www.youtube.com/watch?v=F-GparTbch0

In the past I configured mine to run at 400 rpm.
No mods to the governor except for a lighter spring on the external linkage.
The biggest problem is that the governor response is poor in relation to fast changes in load.
If you choose to run at 350 rpm I suggest you consider generating DC power with an alternator instead of running your ST head.
I had mine connected to a Leese alternator and it seemed to perform quite well.

Cheers,
Veggie

- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw
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veggie

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Re: 350 rpm 6/1?
« Reply #13 on: September 15, 2015, 12:06:04 AM »

Oh !  and these......

https://www.youtube.com/watch?v=2sgXeDEZyXE

And rbodell's unit at 300 rpm...
https://www.youtube.com/watch?v=qVT-dNWt3I8

650rpm, please keep us posted of your project. Videos are always nice  ;)

veggie
« Last Edit: September 15, 2015, 12:15:39 AM by veggie »
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw
- Changfa S195 (Waiting for a project)

veggie

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Re: 350 rpm 6/1?
« Reply #14 on: September 15, 2015, 01:33:04 AM »
650rpm,

I run my Listeroid at 350 rpm.
Runs nice and steady. Exhaust is very quiet.
The alternator is a Delco 33Si spinning at 3000 rpm making 95 amps (1140 watts)  @12 volts.
The engine only makes about 2.5HP at this speed.

https://www.youtube.com/watch?v=rv_DkuBneSs

Veggie

EDIT: Ooops ! I accidentally deleted this video onYtube. Jump ahead in this thread for an updated version.
« Last Edit: October 15, 2015, 12:26:31 AM by veggie »
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw
- Changfa S195 (Waiting for a project)