Retrofitting a direct-drive generator head (Marathon)

[jtodd]

I've got a Marathon Pancake generator head, and I'm wondering if anyone has seen any "pre-built" kits that would convert a direct-drive generator head into something that could be driven with a pulley.   It would have to be a precision-milled ring that would fit onto the outside of the generator and bolt down, and then a shaft and bearing to support the pulley.  I suppose I could get something like that made (my machine shop skills are not quite at that level) but I'd probably end up paying more than I did for the generator.  I was hoping that someone here has seen something that would allow an easy conversion so I can use this generator with my belt-driven smaller engines. (Lister CD)

Something like this is what I have (though of course, not this exact generator).  In my generator, there is only one "end" of the shaft, meaning that there is only a single bearing in the whole generator.  The other end of the shaft is supported by where it bolts to the crank of the engine.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120143515510&ssPageName=ADME:B:SS:US:1

JT

[dmp]

JT

Look up Hayes Mfg.  I have one of their bearing supported stub shaft assemblies.  You may be able to adapt this for
your gen but it's expensive.  Maybe you can get some ideas and make or have one made for you and save $$.

David

[jtodd]

JT

Look up Hayes Mfg.  I have one of their bearing supported stub shaft assemblies.  You may be able to adapt this for
your gen but it's expensive.  Maybe you can get some ideas and make or have one made for you and save $$.

David

Thanks!  They look like they have what I'm looking for, or could make it (hopefully they have it on the shelf.)  And now armed with some correct words, I'm sure I could also look up other companies that have the products if they don't have it.  I think one of the biggest problems here is that I don't know the terminology, so it's difficult searching or even asking for what I'm looking for.  "bearing support" or "flywheel housing" or "pump mount plate" is probably what I'm looking for in some version or other.  I think I'm stuck buying one, since I don't have the time to build such a precision part at this point in my project. 

JT

[dmp]

JT

Off shelf or not, this would cost $400.00 or more.  Think you'd be better off finding a 2 bearing gen.
My thoughts.

David

[jtodd]

JT

Off shelf or not, this would cost $400.00 or more.  Think you'd be better off finding a 2 bearing gen.
My thoughts.

David

Well, the inexpensive (used) Pancake style Marathon generator I bought is just a stalking horse for eventual upgrade to a bigger Marathon generator head, like a 15 or 20kw version.  Those are a bit pricey on the new side ($3500?  $4500?) but can be found with some regularity on the used market, either via eBay or auction.  These devices produce what appears to be much cleaner power, and have a higher quality of manufacture than the ST-type heads from China.  So, with whatever experiences I gain from my 3kw gen head I will be able to apply to a larger generator to attach to my CS 16/2, and then either sell the smaller unit or use it as a backup and leave it on the CD.  While I agree that it will probably cost a few hundred dollars to do this first conversion, I expect even buying two adaptor systems will work out to being cheaper than a new "big" Marathon, or less headache in the long run than trying to clean up the power from an ST.  I think that the first smaller rig would sell for a decent price to someone who is looking for a higher quality solution, so I don't think I'll lose much money.

JT

[phaedrus]

Hi JT!

How bad can the ST power be? I would think that the single phase ST output, which exhibits voltage changes that vary with the load on the opposite leg, would be pretty easy to fix, and cheap to do, if a fella really wanted to do it. Cheaper than the work you are considering.

Really sweet power is cheap from the sinewave inverters if you really have to have it, and batteries are rocksolid stable. This is even cheaper that "fixing" the ST series.

I have a nice direct drive kubota driven 10 kw industrial lighting plant sold by ingersoll-rand, very nice output, and also a 6-1 driving  the cheapest ST 5  I could find and that output is good enough. Not as sweet as the IR set, but ok, and it gives no trouble at all running 'puters and solid state gadgets and pumps and so forth.

Ofentimes I find myself solving problems that don't actually need solutions. I had all sorts of "problems" sighted - most never materialized. Instead the problems were really ordinary - concrete forms that did not quite hold, splices in the first (expensive) ST 5 generator that weren't soldered. Very ordinary stuff.

Provided that the marathon is bolted to a really solid surface - this would take some doing, then the input end of the rotor can be supported - but the marathon shaft is obviously not designed to take the bending moment that an outboard stubshaft and bearing is going to create. This implies that you will need to mimic the presence of an engine with 2 outboard bearings, not one. I make a living building machinery and overhauling power plant machinery - generally turbines - and that's my opinion. I am assuming the marathon is engineered for mounting to an engine flange and not simply adapted.

Much of the "problem" with the ST output is cyclic variation from the prime mover. I expect that the marathon is designed to be driven by at least a 3 cylinder engine. Your twin may produce troublesome and disappointing similar power output qualities.

Best of luck,

P

[jtodd]

[snip]
I have a nice direct drive kubota driven 10 kw industrial lighting plant sold by ingersoll-rand, very nice output, and also a 6-1 driving  the cheapest ST 5  I could find and that output is good enough. Not as sweet as the IR set, but ok, and it gives no trouble at all running 'puters and solid state gadgets and pumps and so forth.

Ofentimes I find myself solving problems that don't actually need solutions. I had all sorts of "problems" sighted - most never materialized. Instead the problems were really ordinary - concrete forms that did not quite hold, splices in the first (expensive) ST 5 generator that weren't soldered. Very ordinary stuff.
[snip]

That is quite possibly the case.  However, it keeps me off the streets at night.  :-)  I tend to approach things with a bit of "overkill", to which some of these pictures may attest:  http://www.loligo.com/lister/pictures/ 

[dmp]

JT

Only looked at two pics.  Certantly looks like you have quite the ability to set up a shaft and pillow block arrangement.
Baffled...

David

[phaedrus]

Well John it certainly looks like you've been busy at home for some time! Nice looking work. I suppose it's a matter of goals as well as style, something that differentiates each of us. Although I enjoy doing and seeing a well executed job, I saw, and continue to see, the diesels in general and the lister types specifically as interim solutions to remote power needs; needs that must necessarily be taken up by solar power, primarily, in the near future. They're pretty, but they're just tools to me. Others seem to see, and to find, these machines as providing other needs. When I worked in nuclear power for GE I saw and worked on some really beautiful "one-of" machines that worked poorly or actually amounted to traps. Thus one cautionary metaphor about overkill I'd offer, one I remind myself of often: "an elephant is a mouse built to government specification" (Robert Heinlein)

Best of luck with the marathon project!

[gotcoinc]

I was reading your post and had to laugh. It does not pay to rework a generator. If you are going to get a bigger generator do you self a favor
buy a standard engine and a generator to match check ebay there plenty
new alternators 15 to 20kva class.
the issue of light flicker less than 3 cylinders is a real annoyance best solution
comerical 3 cylinder engine
I have bought new lister tr3 lpw4 lpa3 new surplus less than 2k.
the T range is the best engine out there IMO.
Why would you buy lister clones and they have to rework them and still have problems.

I've got a Marathon Pancake generator head, and I'm wondering if anyone has seen any "pre-built" kits that would convert a direct-drive generator head into something that could be driven with a pulley.   It would have to be a precision-milled ring that would fit onto the outside of the generator and bolt down, and then a shaft and bearing to support the pulley.  I suppose I could get something like that made (my machine shop skills are not quite at that level) but I'd probably end up paying more than I did for the generator.  I was hoping that someone here has seen something that would allow an easy conversion so I can use this generator with my belt-driven smaller engines. (Lister CD)

Something like this is what I have (though of course, not this exact generator).  In my generator, there is only one "end" of the shaft, meaning that there is only a single bearing in the whole generator.  The other end of the shaft is supported by where it bolts to the crank of the engine.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120143515510&ssPageName=ADME:B:SS:US:1

JT

[dieselgman]

Roger,

If you haven't already figured it out, messing with the clones is fun and entertaining. This is one of the major reasons folks mess with the antique engines! It is a hobby - pure and simple. It has nothing to do with economics although there is at least one train of thought that also would look at these as practical failsafes for a time of severe disruption in our world. So while it may not 'pay' to do some of these crazy experiments... that judgment would also have to include the satisfaction of doing something yourself and learning all the while. I have seen some fantastic functional machines built out of the junk heap before and have to look on some of those as brilliant and inspiring! Yankee ingenuity (as well as others) is alive and well here!

That said... JT just find a 2-bearing generator head and you will be far ahead!

dieselgman

[jtodd]

Roger,

If you haven't already figured it out, messing with the clones is fun and entertaining. This is one of the major reasons folks mess with the antique engines! It is a hobby - pure and simple. It has nothing to do with economics although there is at least one train of thought that also would look at these as practical failsafes for a time of severe disruption in our world. So while it may not 'pay' to do some of these crazy experiments... that judgment would also have to include the satisfaction of doing something yourself and learning all the while. I have seen some fantastic functional machines built out of the junk heap before and have to look on some of those as brilliant and inspiring! Yankee ingenuity (as well as others) is alive and well here!

That said... JT just find a 2-bearing generator head and you will be far ahead!

dieselgman

The short form is that I sold the generator head and the Lister CD, but I still have the 16/2.    I've got an ST-10, and I'll probably end up getting a 3-5kw PMG if I can find someone who makes a quality one in the next few years, but I'm in no rush.  My Lister project has suffered from lack of space, and will probably sit for the next year or so anyway, 95% complete.  I've built a Changfa-195 based generator which works for my purposes in my current home, and when I start building a new house I'll get the pole barn up first, get the genset assembled, then start making power for construction.  I've also got an SR-1 complete generator system, but I need to find brushes for the interesting 110v/12v generator head (early 70's vintage.)

JT