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Re: Ballast



Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Chip,

It doesnt really matter whether you put one ballast in series with the pig or put two of them one for each leg. The input impedance of the PIG and the ballast(s) is a series circuit and the order of components doesnt matter, one is the equivalent of the other.

With the welder as ballast, the secondary load will reflect back to the primary, so with the secondary opened, the primary will have a high input impedance and little current will flow. When you short out the secondary the current flowing in the secondary is determined by what tap (or dialed amount) you have set for the secondary and the "leakage" inductance as seen by the secondary (welders are designed with significant leakage flux). The higher the tap, the more secondary turns, the larger the secondary open circuit voltage, and the larger the secondary current. As the number of secondary turns increases the turns ratio N increases (N is still less than 1) and the primary current will be the secondary current * N.

Gerry R


Original poster: "Chip Ford" <chipford@xxxxxxxxxxxx>

O.K. I have found a pic of a ballast diagram. I can see in this diagram that it is wired in series with (1) leg of the 240 ac feeding the input transformer. Is this the normal configuration? Or should one ballast both legs? Also what is the talk about running the welder leads in the open curcuit. I guess that shorting these leads will increase the ballasting effects of the transformer. I have welded quite a bit with a buzz box. I can remember the change in the sound of the transformer when an arc was present compared to when it was not. So I am lead to believe that when you ballast with a transformer, You only use one set of the windings. the secondary leads can be left open, shorted, or have a load connected between them. A resistor perhaps??? Am I correct. I can't quite wrap my head around what it will take for me to determine the amount of ballast I will require...Let's keep talking...

http://hot-streamer.com/temp/Ballast.JPG

Chip