Weldernator Mk. II, portable version

Ian

Notorious member
Now down to the real project, after proving the concept with the on-board unit in my pickup.

Most of my welding needs are covered by 6010, 6011, and 7018 rods of the 1/8" flavor, so DC amp requirements are under 150 and a lot closer to 90-120 for the digging rods. The concept build showed that 25 volts is a good minimum for arc length, and 150 amps is my predetermined maximum need, which equates to 3750 Watts of power. The alternator system I'm using is about 57% efficient at converting mechanical to electrical energy, so means I need a 6600 Watt powerplant, or just under nine horsepower not accounting for other losses.

For starters I sourced a free but locked-up 11 HP B&S Vanguard engine and got it running after honing the cylinder, grinding the valves, replacing the carburetor, and repairing a bunch of other odds and ends. Next challenge was the drive pulley, since I insist on the efficient and torque-capable multi-V designs and none exist for a 1" keyed shaft. I bought a new Chevrolet crankshaft pulley and a 1" keyed hub from Tractor Supply, then turned the hub back on the lathe to make a pilot and clamping face for the pulley, then drilled and tapped three bolt holes to marry the two.

That's as far as I got so far, now to fab an alternator mounting bracket, adjuster, frame for the engine, convert another alternator, and rig up a control panel and all the diode blocks.

The engine doesn't have an electric starter but does have an alternator and it does work. The regulator/diode module was bad so I grabbed a new one off A-zon for $8. This will keep the system battery charged and hopefully keep the battery voltage a little above static level when powering the weldernator field. If I get the pulley sizes and RPM correct, I should be able to run brushed power tools on this system without any difficulty.

The control panel will have gauges for welding output voltage, field voltage, battery/charging system voltage, a rheostat for controlling field voltage, a "weld" switch that powers the field, and remote kill switch for the engine. I'll also put an electrical outlet on it for running power tools.

On the way are rectifiers, a big heat sink, and some other small parts.

Here's a photo of the engine and pulley with the weldernator mocked up in place and wearing the wrong pulley. I'll put a 2.5" pulley on there when mounted for real and about a 31" 6-groove belt.

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Brad

Benevolent Overlord and site owner
Staff member
Is this going to be trailer mounted for towing with a 4 wheeler?
 

Ian

Notorious member
I'm doing my best to make it "pick up and put where I want it" portable, but the engine and alternator alone weigh nearly 100 lbs together. I'll built a light frame with hoop handles coming up on each end just to mount the control box and use for lifting, and will probably tote it around on a flatbed wheelbarrow. When not out on a job it will have a place under a roof outside the welding shop so I can use it there the rest of the time. $10,000 worth of Blue welders in the shop and I'm planning to use this....well, all I can say is the one on my truck welds that well.

For true portability I would need to drop to a 6.5 HP engine (about half the engine weight) and make it come in under 60 lbs but it would put out a max of about 110 amps DC at 25 volts and that would limit to light welding with 1/8" digging rods and probably only allow 3/32" 7018, which is fine for a lot of things but not for welding fencing pipe.
 

Brad

Benevolent Overlord and site owner
Staff member
100 pounds on a wheelbarrow uphill over rocky terrain? You are either far more of a many than me or a lot dumber?
I am impressed by people who can make things like this work. I am not one of them.
 

Ian

Notorious member
100 lbs in a wheelbarrow is a helluva lot better than carrying it, even uphill on rocky, winding foot trails. I packed rolls of fence wire, dozens of Tee-posts, 10' sticks of 3" oil field pipe, tools, and a small generator 100% up hill from the house by hand, not fun but the hardest work is all done now.
 

Brad

Benevolent Overlord and site owner
Staff member
Got in a few workouts, eh?

You need strong backed kids and soon.
 

Pistolero

Well-Known Member
I think I'd put a couple of 13" or so HF wheels on that sucker and a nice pair of
handles and make it into it's own dolly. 100 lbs in rough terrain is "manly", for sure.

Good job, Ian. What is the output of the alternator on the engine? Not exactly sure where you
are getting your 'power tools' 110VAC from, thinking you have 25 VDC from the new alternator
and 12 VDC from the engine on-board alternator.......and ???

Or switchable field inputs to get 25V and 110V as needed? You said "brush" tools, so I guess
110VDC.....two field control setups? This is why the output voltage meter?

Bill
 
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Ian

Notorious member
The field rheostat controls weldernator field voltage (supplied by battery and engine 12-volt charging system) and thus controls output amperage from the weldernator and rectifier bridge; the output CURRENT level (once selected by the field control rhreostat) is reasonably constant at anything over 4500 weldernator rpm. Open-circuit weldernator output VOLTAGE is controlled by crankshaft speed and is fairly linear from nothing to about 120 VDC, max voltage being achieved at near 10K weldernator RPM.

Under welding load, the output voltage drops considerably; I've been setting the open-circuit voltage via RPM to around 70-100 and seeing that pull down to around 25 volts under a moderate welding load (about 90-100 amps), which is just what we need for SMAW. If I need more arc length for the rod and material, I increase engine speed for more voltage. If I need more amps, I increase alternator field voltage. The voltmeters are for observation and I'll establish set points once I find out what they actually are. Field input voltage and RPM will both need to be tuned to the exact load at hand, but can be pre-set in anticipation of the load once those load settings are established.

If I need to operate a power tool, I'll plug into an outlet wired into the same rectifier outputs that the welding leads use and set RPM for the voltage I need (probably max RPM the system can make) and turn down the field voltage until I get only the needed amps/volts to run the tool and not overheat the weldernator during extended use. 100 to 110 VDC and 5-10 amps is enough power for most tools while welding will require pretty much the opposite, meaning less voltage/RPM and near full-field for high current.
 
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freebullet

Guest
Thinking more gearing & a set of wheels. I'd wanna gear it to see 20-25hp but at the final speed the alt works at. 1Small jackshaft should do it, might be luggish under load without.
 

Ian

Notorious member
Oh, it's gonna lug. Problem is the weldernator speed must be way up there to have a usable arc length under load. This is the issue I had with the truck mounted unit at first, I didn't have the engine revved high enough which made a bear to strike an arc and the arc would snuff because I kept having to bury the rod in the puddle. The B&S engine red-lines at 3600 and will probably only be 2500-3000 rpm under load, wide-open, and with a 3:1 belt ratio that will just barely be enough to make enough weldernator voltage under load to work. No RPM headroom to reduce the pulley ratio more.

The pulleys in the photo will give exactly a 2:1 ratio which would help the engine load a great deal, but won't make enough RPM to weld with this particular alternator model.
 
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Bret4207

At the casting bench in the sky. RIP Bret.
At that weight I'd surely follow Bills idea and mount some wheels and handles on the frame. Actually, with that much power available, you could probably add either electric or hydraulic motors to the wheels and have it walk itself to the project site. Even belts and a friction disc drive system wold help. Of course another alernative is to mount the whole deal on an old riding mower frame and drive it off the engine with a removable vee belt or a jackshaft system.
 
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Ian

Notorious member
A riding mower setup wouldn't go half the places I need it to but is otherwise a splendid idea...ditch the deck, rig a swing mount alternator underneath, wire it up and there ya go.

I thought a lot about self-propelled drive and that really is a great idea even if it adds weight and complexity. Using a riding mower rear diff and wheels would be great, could power it with a corded drill motor.
 

Pistolero

Well-Known Member
OK, that is kinda what I thought, Ian. Gotta have enough RPMs to make the desired voltage AND current, then
adjust the field to get the exact power combo you need.

You have been welding with the other one, so at least you know it will work, as long as the motor RPM and
power will work out properly.

Interesting project.

Bill
 

Brad

Benevolent Overlord and site owner
Staff member
You need a mule, the original 4 wheel drive hauling vehicle. Be a good pet for the kids. Best of all they have no mechanical parts for you to repair.
 

Bret4207

At the casting bench in the sky. RIP Bret.
And if the mule had a PTO shaft sticking out it's backside he wouldn't even need the engine! Talk about gene splicing!
 
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freebullet

Guest
Didn't realize ya had that much gearing on those pulleys.

Far as mobility, had an idea...

Making a skid steer 6x6 or 8x8 ride on powered wheel barrow for my old man. Gunna have a 10hp e start subaru single cyl.
One end will have a winch powered log claw to place logs in the verticle splitter without lifting. Thinking a similar contraption might handle your terrain & gear moving needs.
 

Ian

Notorious member
It really needs tracks to handle some of the terrain around here. One of those sub-compact excavators with a grapple and some hydraulic outriggers added would be the cat's pajamas for moving heavy crap like engines and transmissions around. Your 6x6 idea is pretty neat for schlepping logs and saving backs.


Today I got the front plate cut out and finished for the weldernator mount and also bored another pulley for the 7/8" weldernator shaft. This will give right at a 3:1 drive ratio.

8675
 

Ian

Notorious member
It will be a fixed adjuster, I was trying to save weight originally. It will be mounted on wheels now that I realize how heavy it's going to be anyway and was given some good suggestions about wheels. If it needs an automatic tensioner to force more belt wrap on the little pulley I left myself the option to mount it on the part sticking up above the big pulley. The plan right now is slot a bar on one end and just lock it in place.