Your right. I did my math in my head without reasoning everything out. 3600 Hz ripple is right for a 12 pole 3 phase alternator at 6000 RPM.
I can easily excuse my ignorance when it comes to electronics, however I embarrass myself when I make an error in a simple calculation such as the one that I made in the original post.
As far as the regulation goes you will have a bit of power drift with a simple current limited exciter system.
One of the more desirable features of TIG welding is the ability to modualate the power while welding. That is accomplished by using a foot pedal much like used with some musical instruments.
My power pedal utilizes the internal mechanism out of a Casio keyboard volume pedal. I replaced the 50k Ohm POT with a 10k Ohm POT and then installed the mechanism in an aluminum housing that I made to replaced the Casio plastic housing. I copied this concept from the Weld Talk forum and then Kicked It Up a notch by building my own housing.
I built a 100 amp one back in high school that worked surprisingly well once I found out about the need for the reactance coil.
I failed to mention that I'm running the alternators AC current through a 300A/1000V 3 phase bridge rectifier. Does that eliminate the need for the suggested line reactor?
I just ran the output through the secondary windings on an old 30 amp battery charger. It was a dual half wave with a center tapped secondary so I just reconfigured it to have both halves parallel for 60 amps.
Being the duty cycle was low and its DC current it worked well enough. The old battery charger windings would overheat about the same time the alternator did.
I chose the 270A Leece Neville so as to avoid running against the maximum output capability. Several professional welders have stated that while their machine is rated at 250A they seldom use more than 160A. There are several companies that offer 160A and 200A machines so I can only assume that the experienced welders prefer not to buy machines that would require being ran at it's maximum output.
With an auxiliary fan for cooling the alternator combined with a 50% demand on it's capability I hope to have a 100% duty cycle.
Most TIG work is done with AC and is very fussy about its power source and control so don't expect much from it if you are going to use an alternator for a power source.
Welding aluminum requires the use of AC current along with several variable parameters and yes they say that it can be very fussy. On the other hand welding steel rquires the use of negative DC current with power being the only variable parameter.
Ideally TIG needs an additional high voltage and high frequency superimposed on the main arc to help stabilize it and thats not so easy to add on to a homemade alternator welder.
I have already built a High Frequency arc starter and stabilizer which consist of France 15kV transformer, a couple of spark gaps, 590pF.30kV capacitor, 1 Ohm/10W resistor and the inductance coil.
Now that I have switched to the alternator I will have to build another HF box that ultilizes an automotive coil for the high voltage source.
I don't mind building another HF box because the existing unit scares the heck out of me.
Yep,
I'mClueless