I have been wondering about this for some time since the thread on
electricity usage a short while ago.
I have a Oxford 180 Amp arc welder. The tapping's on the primary allow
from approx 210 to 440 Volt if memory serves at all.
The power factor on the unit will be horrific being mostly a reactive load
so was considering trying to fit a power correction capacitor to save a bit
of current in the supply cable the question I have to the group is how
would the cap or caps be fitted.
I only use it on 240 Volt supply so
could fit a cap across that tap to neutral.
I could fit a cap across the 440 volt tap to neutral and still feed on
the 240 volt tap
I could have two caps one from 440 volt tap to 240 volt tap and another
across 240 to neutral and feed across this.
It has been a long time since I did any phase diagrammes or problems of
this sort so assistance is always appreciated.
The use of one of the cheap Maplin power meters should give a good idea of
power factor on idle current and how the output tapping's affect it. so I
guess it will always be a compromise no matter what value I fit.
- posted 15 years ago