[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Arc welder as pig ballast not working right



Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Hi Nick,

Is is possible for you to use something else for current limiting (reactive or resistive)? Maybe a pair of MOTS with the primary's in series and their secondary's shorted out? Someway to pull the welder out of the circuit. I doubt you have 50 amps at the gap. Likely your losing a great deal of power "somewhere". Thus, my attention to the welder. Also, Check connections getting hot after a run and any possible carbon tracks (shorted turn, tracks inside, or on anything the wiring is near).

Good luck,
Bart

Tesla list wrote:

Original poster: "seanick" <edgarsbat@xxxxxxxxxxx>

Greetings, Coilers of the world...
I bring to you a conundrum, or at least something which makes no sense to me. I have an 8" coil run by 10 KVA pig and a large old arc welder which has 10 or 12 different places to attach the leads, plus 2 ground choices. I have noticed lately that when I use the lowest power setting it works great, however at any other setting past that, my coil does not run continuously but becomes staccato and has much reduced output. I am using a synchronous rotary (@3600 rpm) with 4x 3/16" tungsten rotating electrodes and two stationary electrodes at 180 degrees offset, which are both adjustable remotely while the coil is running similar to Bart Anderson's rotary; adjusting the phase for the different power levels does not result in longer arcs than with the lowest setting though. I am only getting something like 4 feet which is WAY too low for the components I am using.


The ballast at the lowest setting draws 17 amps when in series with the pig, and 50 at the highest setting, according to a clip-on ammeter. The arc welder itself works as expected; each higher setting results in more heat at the weld. What could cause this behavior? So far I only have two theories but I doubt either of these are the problem...
1. Quenching of the gap - reason I think this might be it is that I threw an electrode with an earlier revision of this gap. I have since installed aluminum sleeves with set screws to hold the electrodes. this seemed to cure the problem; now the electrodes are not even all that warm right after a relatively long run.(15 minutes of tuning cycles...)
2. power factor? I don't really know, this is grasping at straws.


What could be the problem? has anyone ever experienced this sort of problem before? It baffles me, because I have never had so much trouble getting a long arc before. NST's and MOT's both outperform this pig, yet I know the pig is good and I can pull huge power arcs from it. I weld with the same welder, and have used it as the MOT ballast with much success until the MOT's burst into flame...

Thanks in advance for any suggestions you can give!
SeaNICK

here is some of the data generated by classictesla, it saves me from typing it all in manually and has a formatted output.. thanks Bart for the consolidate function!

J A V A T C v.10 - CONSOLIDATED OUTPUT
Wednesday, August 10, 2005 08:57:36
Units = Inches
----------------------------------------------------
Secondary Coil Inputs:
4.125 = Radius 1
4.125 = Radius 2
27.5 = Height 1
75.5 = Height 2
1190 = Turns
18 = Wire Awg

----------------------------------------------------
Primary Coil Inputs:
5 = Radius 1
8.15 = Radius 2
24 = Height 1
24 = Height 2
9.45 = Turns
0.25 = Wire Diameter
0.04 = Primary Cap (uF)
0 = Desired Coupling (k)
----------------------------------------------------
Top Load Object Inputs (dimensions & topload or ground connection):
Toroid #1: minor=9, major=27, height=82.5, topload
----------------------------------------------------
Secondary Outputs:
121.01 [kHz] = Secondary Resonant Frequency
90 [deg°] = Angle of Secondary
48 [inch] = Length of Winding
24.8 = Turns Per inch
0.00003 [inch] = Space Between Turns (edge to edge)
17 [awg] = Recommended Wire Size
2570.2 [ft] = Length of Wire
5.82 = H/D Aspect Ratio
16.41 [ohms] = DC Resistance
34435 [ohms] = Reactance at Resonance
34919 [ohms] = Forward Transfer Impedance
12.64 [lbs] = Weight of Wire
45.29 [mH] = Les-Effective Series Inductance
43.841 [mH] = Lee-Equivalent Energy Inductance
47.143 [mH] = Ldc-Low Frequency Inductance
38.194 [pF] = Ces-Effective Shunt Capacitance
35.954 [pF] = Cee-Equivalent Energy Capacitance
58.107 [pF] = Cdc-Low Frequency Capacitance
7.479 [mils] = Skin Depth
27.287 [pF] = Topload Effective Capacitance

----------------------------------------------------
Primary Outputs:
120.77 [kHz] = Primary Resonant Frequency
0.2 [%] = Percent Detuned
0 [deg°] = Angle of Primary
32.53 [ft] = Length of Wire
0.083 [inch] = Average spacing between turns (edge to edge)
0.875 [inch] = Primary to Secondary Clearance
0.064 [k] = Coupling Coefficient

----------------------------------------------------
Transformer Inputs:
240 [volts] = Transformer Rated Input Voltage
13800 [volts] = Transformer Rated Output Voltage
725 [mA] = Transformer Rated Output Current
60 [Hz] = Mains Frequency
240 [volts] = Transformer Applied Voltage
17 [amps] = Transformer Ballast Current

----------------------------------------------------
Transformer Outputs:
10005 [volt*amps] = Rated Transformer VA
19034 [ohms] = Transformer Impedence
13800 [rms volts] = Effective Output Voltage
17 [rms amps] = Effective Input Current
4080 [volt*amps] = Effective Input VA
0.1394 [uF] = Resonant Cap Size
0.209 [uF] = Static gap LTR Cap Size
0.3634 [uF] = SRSG LTR Cap Size
461 [uF] = Power Factor Cap Size
19513 [peak volts] = Voltage Across Cap
68979 [peak volts] = Recommended Cap Voltage Rating
7.62 [joules] = Primary Cap Energy
592.3 [peak amps] = Primary Instantaneous Current
92.3 [inch] = Spark Length (JF equation using Resonance Research Corp. factors)


----------------------------------------------------
Rotary Spark Gap Inputs:
2 = Number of Stationary Gaps
4 = Number of Rotating Electrodes
3600 [rpm] = Disc RPM
0.1875 = Rotating Electrode Diameter
0.1875 = Stationary Electrode Diameter
6.5 = Rotating Path Diameter

----------------------------------------------------
Rotary Spark Gap Outputs:
8 = Presentations Per Revolution
480 [BPS] = Breaks Per Second
69.6 [mph] = Rotational Speed
2.08 [ms] = RSG Firing Rate
9.335 [ms] = Time for Capacitor to Fully Charge
1.12 = Time Constant at Gap Conduction
-1.78 [ms] = Electrode Mechanical Dwell Time
67.24 [%] = Percent Cp Charged When Gap Fires
13120 [peak volts] = Effective Cap Voltage
3.44 [joules] = Effective Cap Energy
437604 [peak volts] = Terminal Voltage
1652 [joule*seconds] = Energy Across Gap
109.6 [inch] = RSG Spark Length (using energy equation)