Micro CoGen.

Nevermind, found it!  http://www.microcogen.info/index.php?topic=460.0

I can't remember if it was from a post on here, or an article on utterpower or somewhere else that talked about rewiring the ST generator heads that puts the coils at 180* separation instead of 90* to help with groaning from imbalance.  I can't seem to find it, does anyone remember where it was?

Can someone tell me what this component in the big red circle (believe it's an inductor?) is?  It had a heavier gauge black wire that ran from from I believe U4 to U2 and wrapped around the component itself twice.  As far as I remember it had no connections to itself other than the wire wrapping around it.  Is it supposed to be for the amp gauge?

Quote from: BruceM on August 03, 2020, 06:05:31 PM
Hey DieselfuelOnly,
Good question, but some more info is needed, though I can make some general suggesti9ns.  You didn't mention the engine, rpm, or ST head size, or whether your setup was 120, 230, or split phase 120/240. Those do make a difference.

Waveform distortions vary dramatically between different ST heads, since manufacturers have varied over the years.  For many applications and specific gen heads that may not be important. Voltage regulation via harmonic with a rheostat or adjustable resistor can be acceptable for many applications too.  Harmonic regulation will in fact handle large, low power factor loads much better than the typical affordable AVR, which does NOT regulate to true RMS volrtage.  

For AVR configuration, many ST3 and  ST5 heads will groan and make vibration noises if imbalanced by running spilt phase loads, or putting an AVR on one leg of a split phase setup.  I suggest avoiding that.  In fact I suggest avoiding split phase setups for these heads entirely.  The 230/240V rated unit sold by CGG in the past will minimize flicker best if installed with the mains only as excitation.  That will eliminate the "harmonic hump" distortion that is pretty band on some ST3 and ST5 heads.  The reason to use the mains is this:  the harmonic wiinding puts out more volts when there is a load, and on my ST3 I have measured the peak voltage at over 400V for starting a 1.5 HP equivalent motor.  It is just 4 skinny spikes per rotation, however, so when compression stroke comes and rpm slows down, so does the harmonic output.  If you put an AVR  using the Harmonic winding as excitation, it can only limit the output of the harmonic.  So for ST heads with properly wound harmonic windings, you are only limiting and already limiited output, and the mains voltage will sag.  If you use the mains for excitation, especially with the 240V AVR, you have some serious head room for the AVR to work with and it will partially correct the voltage sag of the compression stroke.  Either approach will improve the voltage rise during the power stroke.  

For most utility uses like running pumps and motors and tools,  there's little need for precise voltage regulation or worry about Listerflicker.

I hope that helps explain things.  I've been inside 5 -ST-3's and designed my own AVR electronics. A long time ago I offered a flicker reducing AVR plan as open source, and have thus seen oscilliscope shots of a few ST-3's ST-5's and a couple ST-7's.  Some have acceptable waveform distortion, the worst have such bad ratcheting around the peaks that I wouldn't run them myself.  With lots of distortion, some mechanical timers will groan and get hot, and motors will get a bit hotter and be less efficient, power wise.  A good AVR set up will reduce flicker as much as SOM type flywheels, and I've also posted that comparison publicly.  AVR flicker reduction is reduced as the head gets larger, because of the lag of larger inductance in the larger excitation coils.

My neighbor is running a CGG ST-3 with a cheap China 230V AVR.   It works well, but he keeps a spare on hand as they typically fail every 2-3 years, though he does put on perhaps 600 hrs/year.  They are similar to the units CGG sells, he was out of 230V at the time.  We tried to use the 120V AVR CGG sent with it but it made the ST set up as 230VAC moan from the small load imbalance.   I have also not been impressed with the quality of newer ST heads-  harmonic windings are so wrong (very high voltage and no rheostat)  that they can't be used without an AVR, and we got a head with aluminum rotor windings that failed open in 6 months.

My ST-3 on a homebrew AVR has been very reliable.  If I've got to run something  with a nasty PF like a small MIG welder, I flip a switch to go back to harmonic.
Bruce






The huge variation explains why some think ST heads are fine, while others really suffer.  

Thanks for the info.  I have an older (manufactured in 98 or 99 I believe) ST-10 head.  It's extremely heavy compared to the new ones weighing around 400lbs+.  It'll be powered by a 2TNV70 Yanmar so I only expect around 5kw output, if even, out of it.  Direct drive @ 1800RPM.  I'd prefer to go split phase 120/240 as I do have some 240v loads.  Perhaps I should see how it performs with just the rheostat first.  If I start experiencing some bad groaning from unbalanced loads or issues with over/undervoltage on the legs I'll investigate further.  It seems the best setup is running parallel 120v and then using a center tap transformer to get 120/240v output, but that's cost I'd prefer not to take on if I don't need to.

My ST generator has the old rheostat on it and while I'm removing the doghouse and redoing everything I figured I might upgrade it to an AVR.  I see the that Georgia Generator has a few different options, one that appears to use one of the two 120v legs to do the regulation, and the other that uses the voltage across both legs to do the regulation.  Any reason to go with one over the other?  I'm guessing that the 120v regulator could be used with the generator in both 120v or 240v configurations, whereas the 240v regulator would require the series wiring at 240v to function.  The advantage I see to the 120v regulator is that it can be used to bypass the harmonic winding for excitation, where it appears the 240v one can't.  Opinions, alternative regulators, etc?


Here are the wiring diagrams from GG:

240v regulator:
https://www.thegenstore.com/index_htm_files/AVR230-Silver-Bottom-1-or-3-phase.pdf

120v regulator using harmonic winding for excitation:
https://www.thegenstore.com/index_htm_files/AVR115-Black-wiring.pdf

120v regulator bypassing harmonic winding for excitation:
https://www.thegenstore.com/index_htm_files/AVR115-Black-wiring-to-remove-the-harmonic-excitation-winding.pdf

Thanks

Quote from: glort on August 02, 2020, 06:14:40 PM

Given the intended Purpose you are building the setup for, I'd definitely put an alternator of some power on the thing.
If nothing else it would give you the ability to charge flat batteries quickly at least enough to start a Vehicle  where it could be fully charged from there. Using any sort of AC charger is going to take a much longer time and as this will be a mains power generator anyway, you always have that option.

I am also a Big fan of electric cooling. I know a lot of people want belt driven with the excuse of " Bulletproof" But that's really Bullshit.
I have a couple of electric Radiator fans in my Shed window running off a solar panel. They were 15 yo when I got them off a wrecked Subaru Liberty and they have been in my shed window at least 6 years.  I did turn them off for a couple of months a few times during winter but I haven't this year.  I also have a couple on my solar inverters that also run off a panel to keep the inverters much cooler.  These things are literally racking up a MINIMUM of 8 hours a day, sometimes thanks to the higher voltage of the panels, howling their heads off, and they just keep going.  They would easily rack up more hours in a month than most engines will see in at least a couple of years and probably 10 years if they are only for outages.

They are one of if not the most reliable thing I have come across.

It's cheap and easy to buy little electronic thermostat boards these days one can set for precise heat control  from fleabay and alli etc and set them up with the fan so it only kicks in when needed rather than run all the time like a belt fan wasting power, possibly Over cooling ( I have had a Load more trouble with thermostats than I have ever had with fans!) and having a lot more chance of failure when a  belt breaks.

They only run about 8-12A depending on which fan you get as there are plenty out there and one off a Motorbike would probably be plenty for what you need anyway.  Any alternator will keep up  and again you'll have the 12 V Power which you could also use to charge a Battery bank Like a couple removed from Vehicles and put on an inverter to run intermittent loads like a fridge or an LED Light or whatever.  Could be worth it just to run LED lights as they use nothing and you could run a few all night off a car battery for security or whatever and not have to worry about over discharging the battery.  Fire the genny in the morning and you'll soon have the battery back  to 80% at least.  Hook it to a decent solar panel and a little controller to top the thing off and have it at full charge after that.

Thanks for your input, if I do go the electric route it will make things easier as I already have a radiator and electric fan that was mounted on the side of the TriPac box that the engine was housed in.  I've even got the temperature sensors too, although I will probably need to come up with some kind of control system for them as I believe they were controlled by the TriPac's computer.  I actually have 2 electric fans because the condenser had one too.  I guess I need to check their draw and size up an appropriate alternator, as long as it will keep the battery charged and run the cooling fan(s) that's all I'll really need.  I want as little of a load as possible coming from the alternator side of things as I'm not working with a bunch of HP to begin with.  And I agree with the reliability of the electric cooling fans.  Thousands and thousands of hours without issue on every one I've ever had whether it was a vehicle or piece of machinery.

So what's everyones opinion on 12v power for my setup?  The TriPac unit has either a 65 or 120 amp alternator (I'm guessing mine is probably just the 65 amp) alternator, however I can no longer drive it off of the flywheel pulley as I've replaced that with the stub shaft.

So my options are:

1.  Add a pulley to the larger 1-7/16" area of the stub shaft and drive an alternator
2.  Find or make a bracket and new (probably smaller) alternator and drive it off the water pump/crank v-belt like the engine would have traditionally have had
3.  Use a 120v -> 12v trickle charger to keep the starting battery charged and, that brings to another decision I need to make:

Should I use the 12v electric radiator fan that the TriPac unit came with, or find a replacement plastic fan that mounts on the water pump pulley.  If I use the electric fan I will probably also need some kind of a 120v to 12v power supply as I doubt a trickle charger would keep up with it.  

Also I'll need to pick up some square/rectangle steel soon for building the frame.  I'd estimate the total weight of the unit to be in the 600-700lbs weight.  Any recommendations on size?

Quote from: Henry W on July 30, 2020, 09:32:26 PM

Quote from: dieselfuelonly on July 27, 2020, 04:45:20 PM
So if this information is useful to anyone, the engine I'm using is a Thermo King TK270M which is based off of the Yanmar 2TNV70 platform.  These are used in APUs on big trucks and can be got for pretty cheap used.  It seems that the John Deere part # AM875090 flywheel bolts up to either of these engines (the JD tractor this came off of had a 3TNA72 engine), and the stub shaft, JD part # M87178 _should_ be the perfect fit for this flywheel, will verify the fit and dimensions when it shows up.

Good news some of my eBay parts came in today and the flywheel will 99.9% be a perfect fit, will take it to work with me tomorrow where I have the engine and make sure.  But measured everything up for bolting the flywheel to the crank and it seems they are identical.  Ring gears have the same tooth count and I could even move the ring gear from my other flywheel to this new one if need be, but both are in good shape although the new one has slightly more wear.  New flywheel is thinner but that should make no difference for my application.

With the rotational mass of the ST-10, the thinner flywheel will be fine. Looking forward seeing more.

Henry

The other stub shaft came in today and it bolts up perfectly to the flywheel and all seems good there.  Got a lovejoy coupling on the way and took the doghouse off the ST head today and will hopefully find some time to work on everything more this weekend.  Soon I will need to start mocking up a frame.  I think I will create a new thread in the ST generator section that follows the rest of my build.

So if this information is useful to anyone, the engine I'm using is a Thermo King TK270M which is based off of the Yanmar 2TNV70 platform.  These are used in APUs on big trucks and can be got for pretty cheap used.  It seems that the John Deere part # AM875090 flywheel bolts up to either of these engines (the JD tractor this came off of had a 3TNA72 engine), and the stub shaft, JD part # M87178 _should_ be the perfect fit for this flywheel, will verify the fit and dimensions when it shows up.

Good news some of my eBay parts came in today and the flywheel will 99.9% be a perfect fit, will take it to work with me tomorrow where I have the engine and make sure.  But measured everything up for bolting the flywheel to the crank and it seems they are identical.  Ring gears have the same tooth count and I could even move the ring gear from my other flywheel to this new one if need be, but both are in good shape although the new one has slightly more wear.  New flywheel is thinner but that should make no difference for my application.





I ordered this stub shaft and realized afterward it's actually for something PTO related, but it looked nearly identical to the actual one I wanted so oh well.  The bolt circle and dimensions of it seem nearly identical to the actual stub shaft that is supposed to mate to the flywheel, although it has a machined area on the back where it must pilot into something for the PTO.  Looks like I could easily make it work, but the correct one is supposed to arrive by Wednesday so I will wait and see if that one is any different.  I'm hoping the mating surface is totally smooth so it completely sits down into the fingers on the flywheel that align it, which from the pictures on eBay I think it will, but its kinda hard to tell.

The outer end of the shaft is 1 3/8" I believe and the inner area with the keyway is 1 7/16".  I'd probably chop off the outer end of the shaft since the keyway doesn't run all the way down it.  However, I probably wont' end up using this one anyway.




Here are the pictures from eBay of the "correct" one I ordered.  Notice how the keyway runs the entire length and the mating surface of it appears to be totally flat without the piloting step machined into it.

If that ends up being the correct shaft, I will probably keep it at the full length as I could mount a serpentine pulley on the inner area to drive an alternator, etc., and use the outer end of the shaft to drive the LoveJoy to the generator head.  We will see what looks best when it arrives.

I'm pretty excited because it looks like this will all bolt up and end up being a LOT cheaper than having something custom machined.

It would also allow me to upgrade to the larger 3-cylinder Yanmar 3TNV70 / 3TNA72 (which the flywheel is from) / other similar engines which have more horsepower and could probably run the gen head at full output compared to my little 2TNV70 in the future if I wanted to.

I picked up a few more parts from eBay, got a flywheel from a Deere with a Yanmar engine in it for real cheap.  Hopefully it will fit my engine, initially looking at the measurements it looks like it will, but won't really know until it shows up.  Picked up another stub shaft for the same model Deere so I'm hoping this could be a nice bolt-together setup.  Just waiting on parts to show up and we'll see.  By the time I'm all said and done collecting parts for this project I'll have enough to build two 

Quote from: glort on July 23, 2020, 03:57:22 AM

I am after a similar Stub shaft for my Kubota engines.

Anyone know of a source? I'm in Oz but are there any places like tractor joints or types of businesses likely to carry them.... at a reasonable rather than ridiculous price?

eBay has been where I've been having the best luck.  Since my engine is a Yanmar and many JD tractors had Yanmar engines it has been helpful to search for the Deere parts instead of Yanmar parts and that has opened up a lot more options.  If you could find out the applications your Kubota has been used in that may lead you in a good starting direction.  At least from what I've seen any dealer/manufacturer will charge a premium for parts like a stub shaft or flywheel... much much cheaper to go the used route or modify it to work if possible.

So still waiting on a quote from the machine shop about the stub shaft but based on his initial reply I'm guessing it's gonna be out of what I want to spend on this project.  I picked up a stub shaft off of eBay from a Yanmar in a Deere mower that I can probably modify myself to make it work.  The seller told me the flange end of the shaft measures a little over 5", so that that's just a little bit bigger than the belt pulley is.  The back side of the flange end is stepped in so I don't see how I would go about piloting it into the center of the flywheel, so I will need to learn how to very accurately drill the bolt circle for the 4 bolts into the flywheel.  Hopefully I can make it work.  Alternatively, and maybe a better idea, is to drill new bolt holes into the stub shaft rather than the flywheel.  I still see it being a challenge laying this out by hand.



This one isn't the one I bought, but it is what the back side looks like.  I was hoping I could put it in the lathe and machine down the back side to fit the 70mm bore in the flywheel, but I don't think that will be possible.

Quote from: mobile_bob on July 19, 2020, 05:21:16 PM
now if you can mount a stub shaft in the taperlock and then couple that to the genhead with a lovejoy or similar rubber coupling then alignment while important is not as critical.  you could be off a few thousands, which is much easier to accomplish.

I like this idea as I could use the pulley to drive a 12v alternator as the engine doesn't have it's own alternator bracket.  Though I would have to take it to a machine shop to have it milled for the taperlock, and that that point maybe it would be easier to just have the machine shop make a stub shaft that I could either pilot into the pulley or the flywheel.  One thing I would need to check would be the runout on the inside bore of the pulley since it was probably not designed with tolerances to have something else pilot inside of it.   Anyone know of a machine shop around NC that could make something like this for a reasonable price? 

Hi all, new member here thanks for approving my account recently.  I signed up a month or two ago about it looks like there was a problem with lots of bots so I'm guessing registration was put on hold.  I am purchasing a 10kW ST generator head from a member here to build a small diesel genset mainly for backup power for when a hurricane wipes it out for a week here in NC.  

I have a small Yanmar diesel out of a Thermo King TriPAC APU unit off of a Kenworth I used to own.  Ingersoll brands it as a TK270M, and as far as I can tell it is based off of the Yanmar 2TNV70 with some minor changes such as the flywheel and I believe the output is slightly derated as well as it is designed to simply run an A/C compressor and an alternator without the need to run the trucks' engine to stay comfortable.

The data plate on the engine specifies 7.5kW @ 2400 RPM.  I want to do a shaft coupling from the engine to the generator head which obviously means the output will be further decreased as the engine will only be running at 1800 RPM.

I emailed back and fourth for a while with someone from Hayes manufacturing about stub shafts and flywheel couplings and unfortunately the non-SAE flywheel would require them to make a one-off coupling for me at a cost of $938 which, let's face it, is way too much for this project I'm taking on mainly out of boredom.

Another option I have is I have found a flywheel off a similar Yanmar with a SAE bolt pattern that I could use with a Hayes stub shaft, but by the time I purchase the flywheel and stub shaft I'm sitting at close to $600 just to get things turning.

So right now I'm leaning towards creating my own coupling and was hoping to throw some ideas around.

Here is a picture of the flywheel, along with a crude drawing with the dimensions and bolt circles:






Here is the pulley that Ingersoll attaches to the flywheel to drive the alternator and A/C compressor.  It is 5" in diameter and pilots into the 70mm bore in the center of the flywheel after the flywheel is installed on the crank.  It is bolted to the flywheel using the 6 "B" holes on my drawing.






I am no machinist but know enough to get myself in trouble and can sweet talk the boss into letting me use the old wore-out lathe he bought years ago from a machine shop that closed down.  Here's my idea so far:

If I could find an appropriately sized shaft flange, like the one below, and some appropriately sized keyed shaft from Grainger, McMaster, etc., I could put that in the lathe and machine the back side of the flange slightly to create a lip like the original pulley to pilot it into the flywheel.  Then it's a matter of marking and drilling the bolt circle as I'm sure none of these flanges will end up having a 100mm bolt circle like my flywheel, installing a LoveJoy coupling in between my new DIY stub shaft and the generator and off we go.





I guess I could also purchase a short 1" or so piece of 5" round stock and weld a keyed shaft directly to that, but that is probably a bit out of my skill level when it comes to getting everything perfectly true on the lathe.

Thanks for any input and/or ideas.