Gen head hold down

[Stan]

On the following site   http://www.powercubes.com/listers_3.html   is a picture of the SOM base.  On the base are two "tracks" (for want of a better word) that the gen head is bolted to I presume.  How heavy are these tracks?  I have something similar in the shed that were originally meant to be barn door overhead tracks.  They are made of heavy sheet metal and appear to be quite flimsy.  I was loath to use them on my little 2.5kw gen head but looking at this picture, maybe I should. 

This question is to anyone with access to an SOM.  How thick is the metal that these two tracks are made of (guage/thickness in inches or mm).  (I know, I know, a preposition is a bad word to end a sentence with)
Stan

[binnie]

It would be nice to find some examples of the original lister Iron bases for both the singles & the Twins to mount our listeroids on. I wonder if they are still around. I have seen examples only in the original manuals and a few on ebay UK offerings...Might be something to consider with Ken's shipment in the early fall. I am looking over there. Some amazing stuff.

[Stan]

This particular piece of engineering would be dead easy to replicate if I could tell the thickness of the steel "rails" that are on that original SOM foundation.  I imagine from the rest of the site that the SOM gen head is NOT a light piece of machinery and yet it only develops 2.x kw, I assume because in the 50's that was plenty to power a whole household (maybe 2).  Mine is 2.5 kw and only weighs 50 or 60 lbs so would be easy to hold down.
Stan

[GuyFawkes]

This question is to anyone with access to an SOM.  How thick is the metal that these two tracks are made of (guage/thickness in inches or mm).  (I know, I know, a preposition is a bad word to end a sentence with)
Stan

my start-o-matic has a pukka cast base, so I can't answer that question

[Mr Lister]

Guys,

The cast iron T-slot tracks were used in the later Startomatics that used the 46 " x 24" fabricated steel base - from about 1950 onwards.

The cast iron runners are 18" long and 3" wide at the base with a slight trapezoidal draught angle required by casting. They are about 1.75" deep

The T-slots are 1" deep and will accept 1" diameter heads, and 5/8" dia (maybe 9/16) bolt shanks. 

When fitted to the base, the centre distance between tracks is 9.25".

I have taken a couple of photos that I will put on:

http://groups.yahoo.com/group/Lister_CSOG/



Ken

[Stan]

Thanks Ken....The steel for those T-Tracks looks about 1/8" thick (on the newer SOM's).  Am I close?
Stan

[Mr Lister]

Stan,

The T-tracks are cast iron and nearly 3/4" thick.

The actual fabricated steel baseplate is made from 5/16" steel or thereabouts - it takes 2 to lift it - so I'm guessing 150lbs.

It is re-inforced from the underneath with triangulated webbing - like a manhole/drain cover.

Nothing about the Startomatic is lightweight!


I will put some more pictures up on powercubes/listers - hopefully later today.


Ken

[Stan]

Tns Ken....I'll look forward to the photos.  Any idea how much the SOM gen head weighs?
Stan

[Mr Lister]

Stan & List

The standard SOM head weighs somewhere around 150 to 200lbs.

Although only 2.5kVA, it is fitted with an 11" diameter x 2" thick cast iron flywheel/pulley, intended to absorb load transients, without putting undue strain on the V belt drive.

Paul and I struggled to pick up the SOM head and so resorted to my engine crane to sling it into the back of the car.

You may have seen the pictures of my fold up engine crane. It travels with me in the back of the car whenever I go  to work on engines.  It takes 5 minutes to put up, but has save a whole lot of awkward heavy lifting.

I am thinking of a custom trailer that has the crane built in with an extendable jib on a hoist - anything for an easy life ;-)


Ken

[Stan]

Tnx Ken....Another thing I have always been curious about, the diameter of the pulley/flywheel on the gen head that is meant for 60 hz.  I don't have the Lister part number at hand but I can get it for you if you want. 
Stan

OK...It's officially called an "Alternator Pulley"  # 8-8-524  (thats the 60 hz one)

[Mr Lister]

Stan,

I can only assume that most of the pulleys here were intended for 50Hz operation, and that 60Hz is likely to be very rare.

I will ask a friend to measure his 50Hz pulley and then we can calculate 5/6 of that diameter.

The SOM I hauled at the weekend lost its alternator about 10 years ago when someone sold it as scrap ;-(

I found a Chinese company selling adjustable motor mounts for large frame motors that would make mounting an ST a breeze. I will look out the link.

Looks like another voyage for a Chinese Junk



Ken

[Stan]

I assume the gen heads are 1800 rpm?  I can't find anything in the manual that confirms this.
If so, knowing the exact diameter of the flywheels I could calculate the diameter the gen head pulley needs to be to produce 60 hz. 
Stan

[Stan]

OK Ken.....I found the pics of your SOM's t-tracks, WOW are they ever thick!  Mine are made of stamped sheet metal, I don't think they'll make the grade.

OK so I also found that the SOM's flywheels are 25" in diameter.  So the formula should be
Diameter of the gen head pulley = 25" *650 (rpm) divided by 1800 (rpm) = 9.028"  ( assuming 1800 rpm gen head)

9 inches seems about right for 60 hz operation.  How does that compare with the flywheels on the SOMs designed for 50 hz operation?
Stan

[kpgv]

Hi All,
I'm interested in info on the "Cast Iron" SOM bases.
Next time you all are handling one, if you can, please record some general dimensions (H x L x W) and take a peek at the underside.
I am curious to know the size, structure, and weight. With all the trouble some "Roid" runners have with "mounts" and etc. this information might be useful to apply to our setups, and/or consider buying a base from "across the pond", or even having them cast here in N.A. (Can't be too technical, like maybe as simple a job as casting manhole covers etc., only bigger and heavier).
"Fabricated" steel bases or frames will probably never be as "quiet" as good old heavy vibration absorbing Cast Iron.

Kevin   

[Mr Lister]

Kevin & list,

I helped a friend with his 1948 S-o-M yesterday that has the cast iron base.  GF is correct - this is a serious casting and is a minimum of 0.5" thick.

The concept is so simple, after casting, the engine base is milled flat, drilled and tapped to take the engine 13" x 13" bolt pattern.

The T-slots are cast into the base and are cleaned up with a milling cutter.

Machining is minimal, just as the Victorians intended.  As you rightly say, the density of the cast iron is paramount in absorbing the pounding of the engine.

Why dont we get one of the Indian manufacturers to re-instate this base casting. It would only cost about $75 out there, and could be machined to take the common ST alternator sizes.

I took some photos of the base yesterday and I will put these on coppermine if I can. 

Failing that they will go on the www.powercubes.com/listers_6.html page


Ken