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Author Topic: Welding from a Listeroid/ST generator rig  (Read 347 times)

Martin

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Welding from a Listeroid/ST generator rig
« on: February 26, 2021, 10:59:13 PM »
I live off grid and I've been using a Listeroid CS1 (6hp) coupled to a ST generator (7.5kw) for the last six years. Generally, I only run workshop tools from the ST generator. All domestic stuff such as lights, music, computers, etc are supplied from a small (1.8kw) inverter off a 24v battery bank. The battery bank is charged from a heavy duty 24v automotive alternator on the listeroid.

So I want to do a bit of welding and I'm interested to know what your collective thoughts are on running an inverter based TIG welder from the ST generator. I'm not too concerned about power - I accept that I'll have to keep the welding current down otherwise I could stall the engine. What concerns me is the quality of the electricity produced - by that I mean the voltage spikes, etc and whether this will damage the nice new welder that I've already ordered? Do any of you out there run a welder off your listeroid based rig? I'd be interested to hear your experiences and thoughts on the subject.

Cheers
« Last Edit: February 26, 2021, 11:01:28 PM by Martin »

BruceM

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Re: Welding from a Listeroid/ST generator rig
« Reply #1 on: February 27, 2021, 12:38:04 AM »
The typical ST head THD is pretty high from waveform distortions (ratcheting from non-skewed rotor windings, harmonic hump from harmonic winding) will have no adverse affect on your welder.  All the new designs are switch mode power supplies, so the first thing they do is create bulk DC from the AC input.  The cheaper welders with bad power factor (direct rectification of the mains to bulk capacitors may do this in a manner that has lousy power factor.  That will affect an electronic regulator, if you use one on your ST-7, and it is a typical cheapy that doesn't do true RMS voltage regulation...causing it to regulate voltage too low.  I've experienced this situation on my ST-3 with electronic regulation.  On your stock harmonic winding, it will regulate fairly well with a rude, low PF load.  i switchover my ST-3 to the backup harmonic for this situation. 

The usual 10 Hz Listerflicker variation in voltage and frequency will normally be handled quite well by a decent electronic welder.

The big issue I see you having is that you will have to limit your welding current pretty seriously.  If it's a small MIG welder, with output at 24VDC at the machine, you should get 85-90 amps of welding current (allowing for losses), but you're at the limits of the 6/1 power (2300W generated power)  If you can live with that, you should be OK.  I have had a smaller amp MIG welder running on 230VAC, on my 6/1-ST-3 with harmonic regulation. It was fine for thinwall square tube welding.

For moderate current stick or other higher power welding, you don't have the power for 1/8 rods of 7018.  You could barely do 5/32 6013 rods. If your duty cycle was low enough, and you had SOM type heavy flywheels, that would probably help.  An 8/1 would be a better match for home/farm welding. 

PS I've got some heavy flywheels I'd sell at cost if you get serious about doing an 8/1 conversion with an aluminum piston and have the typical 6/1 spoke flywheels.  I don't think anyone thinks they should be spun higher than 650rpm. 

Best Wishes,
Bruce




« Last Edit: February 27, 2021, 12:42:19 AM by BruceM »

Martin

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Re: Welding from a Listeroid/ST generator rig
« Reply #2 on: February 27, 2021, 09:53:39 PM »
Thanks for your reply Bruce. Am I understanding you correctly - when you say you use an electronic regulator on your ST-3, do you mean that you have an AVR on it? Is it one of these?

https://www.amazon.com/gp/product/B07V9HPKWT/ref=ox_sc_saved_title_4?smid=AYAQCA6J7ASI3&psc=1

I looked at them a while ago, but something about the low price didn't inspire me with confidence. Not really a sensible way to judge a product, I admit! Do you find it a worthwhile modification? Are you saying that you disable it when you weld?

I called my listeroid a 6/1 because I run it at 650rpm, but in fact I bought it as a 8/1 and it has the solid flywheels. When I first set it up I found the vibration a bit high, so I changed the governor spring and down rated it to a 6/1, running at the lower speed. It would be a simple task for me to up rate it back to an 8/1 if necessary.

Cheers
« Last Edit: February 27, 2021, 11:30:31 PM by Martin »

BruceM

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Re: Welding from a Listeroid/ST generator rig
« Reply #3 on: February 28, 2021, 03:28:29 AM »
I do use an AVR on my ST-3 and so does my neighbor on his.  My neighbor uses one similar to the one you show, his purchased on ebay.  They last about 4 years so he keeps a spare on hand.  His ST-3 setup IS using the harmonic winding; in fact his CGG "brand" ST-3 requires it, the stock harmonic setup is grossly over-voltage. I use an AVR of my own design; a hand soldered prototype. I can flip a switch and revert to the stock harmonic regulation.  My St-3 had a very nasty "harmonic hump" so I use the mains for excitation of my homebrew AVR.  I also offered a schematic and PCB design for a simple AVR here many years ago.  A few members made them. The China AVR's are so cheap that even I recommend them.  As I said, you should stick to harmonic regulation for a welder as these cheap AVRs won't handle a low PF load like some welders well, and will regulate at way too low of an true RMS voltage.  I learned this the hard way, though it was not a welder.

I'm happy to share schematics, etc. with a forum member who needs them.  You can't buy parts for what you can buy the finished China product for these days.

Since you have an ST-7 and what is really an 8/1 already,  you have all the makings of a good welder generator.
Balance issues are easy.  I highly recommend 38AC's method.  I used it on my neighbor's 8/1 and will never go back to the Mr X wheel chalking method.  The latter works, but takes much more time.  38AC first corrects the counterbalance offset angles to match the key location, then adds weight to the lighter of the two wheel's counterbalance weight to make have identical on-axis counterbalance weight as measured by string can and weights..  Then you just add equal weight to each wheel either at or opposite the counterbalance.  Hoppers need more, fore and aft movement or sliders need less. 1 oz per each wheel increments work OK.  It's can be done with only a handful starts/stops.  My hat's off to 38AC for this simple, powerful method.  I used a short, leveled section of hot rolled angle iron on wood blocks and a 12" section of 2" OD axle from Amazon for doing the measuring and matching. Plus a can, string and lead shot.

I would rather not limit myself to 2300 watts continuous for welding if I already had an 8/1 and ST-7!
The faster rpm of the 8/1 does seem a bit "nervous" for a while but it grows on you.

Best Wishe

« Last Edit: March 03, 2021, 07:19:23 PM by BruceM »

Martin

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Re: Welding from a Listeroid/ST generator rig
« Reply #4 on: March 02, 2021, 12:30:13 AM »
I did try the chalk method when I installed the engine about 6 years ago, but to be honest, I didn't have much success with it. I deduced, rightly or wrongly, that the flywheel balance was almost insignificant compared to the reciprocating weight of the piston, etc. Perhaps it's time to have another look at it. I'm looking for 38AC's method, but I can't find it. I did come across some posts where other members refer to him leaving the group and taking down his posts. Do you happen to know where I can find a description of his method?

Cheers

BruceM

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Re: Welding from a Listeroid/ST generator rig
« Reply #5 on: March 02, 2021, 09:44:04 PM »
38AC's balancing method in brief:

Take the flywheels off, make some sort of jig to suspend a length of 2" axle or smaller axle with 2" OD bearings in the flywheel.  I used wood, with some scrap angle iron for the load carrying edge for a 12" long piece of 2" rod. I leveled the angle iron pieces with paper and cardboard shims. The angles were screwed to the wood, one edge up.  38AC has a much nicer, welded steel jig- I don't recall details. 

 Set the wheel up on your jig and then add weight at 3 or 9 o'clock as needed to get the counterweight centered exactly at the bottom.  38AC had details on measuring and marking from the gib key slot to insure you know exactly where on the flywheel the top should be, which I've forgotten. You will realize why you need to do this when you see one or more of your flywheels resting way off angle from the key slot.  Measure the counterweight with a string and can weights suspended on the surface of the flywheel opposite the counterweight (63 and 9 o'clock).  Do the 2nd wheel, then add weight to the counterweight area rim of the lighter so it matches the heavier.  Now you have matching flywheels with a known counterbalance that is opposite the gib key.  My neighbor's DES 8/1 had about 43 oz of counterbalance weight, and we had to add about 8oz more (evenly split).

This removes all the "art" from the subsequent dynamic balancing.  Now you just add weight to a hopper until it stops jumping up and down and the head starts moving fore and aft ever so slightly.  Weight should be added equally to both wheels at the counterbalance or opposite (to subtract). 2 oz total increments is fine, double that if it's bad.

38AC mentioned that for fine tuning, a newly rebuilt engine will need a bit of running to loosen up a bit.
Note that for the 8/1 or SOM flywheels, the "counter weight" is by design and a lightening hole.

My memory is poor so I hope maybe 38AC will correct me!
« Last Edit: March 02, 2021, 09:47:12 PM by BruceM »

sirpedrosa

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Re: Welding from a Listeroid/ST generator rig
« Reply #6 on: March 02, 2021, 10:35:45 PM »
Hi Bruce

Don't idolatre Butch, He's just an old guy wom thinks know some stuff.

But a WIS (means well informed source) told me this kind of fly balance by eye ball were passed to him by his grandson (belive me), and his grandkid said this will only will work just in one axis (say X), but you can have an inbalance in Y axis (dont ask me what is it, because I only got elementary school), but for low rpm it will work.

Well, so far some of our members said it works, so maybe it will work also with you.

Stay safe.
VP  ;D ;D ;D

PS: by the way Bruce, how do you call that fly?
« Last Edit: March 02, 2021, 10:38:26 PM by sirpedrosa »
By order of firing up:
Bernard 18A - 1968 (mama's water pump - year of my birth)
Petter PAZ1 - Jun 1967, 3HP, sn 416xxxx
Petter PAZ1 - Nov 1979, 3HP, sn 425xxxx
Lister 12/2 - 12651227, the pearl!

cobbadog

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Re: Welding from a Listeroid/ST generator rig
« Reply #7 on: March 03, 2021, 05:53:57 AM »
This is a very simple form of doing a static balance and is a good start to getting it better than not balanced at all.
With what is called X,Y & Z axis these are terminology used in the machine shops for milling and machining.
These are;
Forward and Back
Left and Right
Up and Down
So I'm not sure how any other axis can come into play here other than the rotational direction on the vertical plane. It should not move left or right nor up and down.
So doing this simple test and correction using stick on wheel weights is the safest way to go because drilling out excess metal is a final one way journey for balancing and only recommended to be done by experts in balancing engines etc.
Coopernook - the centre of our Universe.

38ac

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Re: Welding from a Listeroid/ST generator rig
« Reply #8 on: March 03, 2021, 11:41:15 AM »
It was unfortunate that all my pictures were lost when the photo host shut down this the reason for the vanishing posts here.  No pics equals rest of post worthless. That being said an enterprizing individual happened to save all of my rants so there is hope at some point they will be available with pictures.
Balancing and engine the best and easy way first requires you to get the counterweight in the correct position with respect to the keyway. This is something that is messed up often in India. It is very important step and something you cannot pass by if you want the engine to run as smooth as it can be. To do this requires that you get the engine exactly at top dead center. Then place vertical marks on the flywheels. After that you place the flywheels on a balancing stand as Bruce suggested your marks that you placed previously must be vertical when the flywheel is allowed to freely rotate with the heavy spot down. The Next step is to match the offset weight in the flywheels. The easiest way to do that is to add weight to the flywheel with the least amount of offset weight. To check offset weight requires that the lines you mark on a flywheel be held horizontal by temporary weights attached to the light side. once you have the weight in the correct position and respect to the key way and equally weighted both flywheels you reattach them to the engine and adjust the offset weight to smooth out the operation. If the engine has too much offset weight it will be a scooter while running it will tend to walk across the floor. If the engine has too little offset weight it will be a hopper, up and down. Realize that you are attempting to balance a up and down motion which is the weight of the piston and half of the connecting rod via a circular motion with offset weight in the flywheels. None of these engines well set perfectly still but they can be made very good if you take all the steps. My first attempt at balancing was via the chalk method and attaching weight and I was not successful at it either.

 The link provided here is of a metro 61 that I balanced with my method.
https://youtu.be/p2YwtlfAVfc
« Last Edit: March 03, 2021, 11:45:13 AM by 38ac »
Collector and horder of about anything diesel

sirpedrosa

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Re: Welding from a Listeroid/ST generator rig
« Reply #9 on: March 03, 2021, 05:41:13 PM »
Hi Bruce

Saw? the Master has spoken!

Nice, very nice Butch. And after all, that thing of X, Y  and Z axis was explained for all understand!

Cheers
VP
By order of firing up:
Bernard 18A - 1968 (mama's water pump - year of my birth)
Petter PAZ1 - Jun 1967, 3HP, sn 416xxxx
Petter PAZ1 - Nov 1979, 3HP, sn 425xxxx
Lister 12/2 - 12651227, the pearl!

Martin

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Re: Welding from a Listeroid/ST generator rig
« Reply #10 on: March 03, 2021, 06:03:18 PM »
Thanks Bruce and 38AC for taking the time to explain this method. I think I get it and I will give it a try - not immediately mind you, as I'm in the middle of another project that needs to be finished first.

Bruce, looking at the picture of your flywheel, I can see the counterweight in line with the key slot...the larger of the three "spokes". My engine is from Powerline and the flywheel doesn't look like that at all - see attached photo.

At first glance it looks like there is no counterweight until I saw a hole in the back face of the flywheel rim roughly opposite the key slot. This hole is about 1/2" diameter and about 2 1/4" deep. It's cast, not drilled - it is not perfectly round like a drilled hole would be but rather rough. I always assumed that this hole was for balancing the flywheel, but could it be a lightening hole, to create the effect of a counterweight opposite? If so, it doesn't seem very much! Nothing like your friends 43oz counterweight. Is it possible that the counterweight on my engine is on the crank shaft, inside the engine casing, eliminating the need for a counterweight on the flywheel? I've got a vague memory of seeing something that looked like a counterweight on the crank last time I had the crank case door off...like you though...I can't quite remember! Nevertheless, whether the counterweight is built into the flywheels or on the crank, I would guess that this balancing method could be used. Any thoughts/comments?

Cheers.

Hmm...I'm having trouble posting my photo

Martin

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Re: Welding from a Listeroid/ST generator rig
« Reply #11 on: March 03, 2021, 06:47:26 PM »
Here's the photo of my flywheel:

Martin

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Re: Welding from a Listeroid/ST generator rig
« Reply #12 on: March 03, 2021, 06:52:58 PM »
38AC....I just watched the video of your Metro 6/1. If I can get mine running half as smoothly as that, I'll be very happy...

Cheers

BruceM

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Re: Welding from a Listeroid/ST generator rig
« Reply #13 on: March 03, 2021, 07:37:37 PM »
Thanks for piping in, Butch. I forgot the essential alignment of TDC and counterweight position.  Yikes, that's critical.

Martin, it looks like you've got a machine with no counterweight on the flywheels, which means you need it on the crankshaft.  Better send a picture from the big door so we can see (and learn).  Also- what's the outer diameter of your flywheel?

Maybe 38AC can suggest how to best tune your balance.  I can only guess that I'd apply his same method only getting the two flywheels first balanced to have zero counterweight.  If it was a hopper you'd have the option of adding weight opposite TDC to the flywheels, or if possible, adding it internally to the counterweight.

One guy here many years ago got a zero counterbalance engine-  none internally or externally.  A real Rajkot surprise. 




Martin

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Re: Welding from a Listeroid/ST generator rig
« Reply #14 on: March 03, 2021, 11:36:03 PM »
Bruce, my flywheels are 20" diameter. I've just had a look inside through the crank case door and the crank does indeed have counterweights. I took a few photos, which I'll share as soon as my wife has shrunk the pixels sufficiently to post them here...she's better at that sort of thing than I am!

I agree - it seems logical that I should remove the flywheels and balance them for zero counterweight and then put them on the engine and proceed as you and 38AC described.

From memory, I would say that my engine was a bit of a jumper when running at 850rpm.

Photos to follow.

Cheers.