Hey Benny, think the guy that wound that transfomer was on the *********x

Hood

I can see why you say that, because the winding are not around the core, however its based on the transformer symbol http://www.kpsec.freeuk.com/powersup.htm#transformer
Or are you commenting on my limited freehand skills.

BTW, we used to have a brand of beer here called *********x ( 4 EX) is that what you meant ?

Yes Benny, you have got me right on both counts, just looked like you had been sipping a bit too much of the castlemain(sp?) when you drew the windings, no offence was meant.

Hood

Oh forgot to say I got the transformer hooked up today, with the 440 instead of the 415 across the phases I am getting 54V ac  which once rectified and smoothed is giving me 80V dc no load and putting a bulb accross it drops it to 78v which is perfect. Only thing I am wondering is whether it will drop further with a bigger load, time will tell.
 Put the scope on it and and there doesnt seem to be any ripple whatsoever so it should be ok. BTW sorry for poor quality pics, my phones camera isnt very good but for £6.50 I cant complain
Hood

An AC arc welding transformer is designed to give a reasonably constant current at any particular setting. If the arc length is varied, the volts go up or down to control the current. The set is said to have a drooping characteristic (oo-er!). So the output is not regulated, unlike a close coupled power supply transformer, where a good design will hold the voltage within about 10% for any current drawn within its rating. Rectifying and adding capacitance will smooth the output but if the load drawn is varied the voltage will also vary. If your load current is reasonably constant you should be OK. It will be very interesting to see the results of your experiment. I am not an electronics expert but did sell welding equipment a long time ago.

Good luck!

Ian

Thanks Ian, knew it was too good to be true. I would think the volts required will vary quite a bit as it is the voltage that gives the speed of the servo. Oh well, will give it a go and see but looks like it wont work too well

Hood