[Prev][Next][Index][Thread]
Re: ballast/reactors
Yes this is a duplicate,i noticed a few people interested in ballasts
on the net, so instead of going through the motions again i reposted it,you
never know who reads these things? some people still think all reactors have
cores of u235/p239
A reactor is a device that controls the inductive reactance of a
circuit,the principal property of an inductance is to resist any change in
current through it,and therefore any inductance in a circuit will impede the
flow of alternating current.Your arc welder is a reactor,limiting the
short-circuit-current to your transformer.The ideal way(cheapest)to control
the reactance is the saturable-core reactor,this consists of a magnetic core
with D-C and A-C windings,dc controls the inductive reactance of the ac
winding,more dc=less ind.reactance and vice versa.The ac and dc winding can
not share the same core,the flux linked with the dc winding can't be affected
by the ac current in the ac winding.I'm not up on the drawing method used
here on the net,so if you can visualize a figure 8 the dc winding goes
around the center bar ,the ac winding goes around the top bar exits on the
right goes down to the bottom bar enters on the right and exits on the
left,the windings need to be wound in phase(same direction).Using a figure
eight core with the two ac coils, produce flux in opposite directions through
the central core on which the dc winding is wound.Therefore,the currents in
the ac windings neutralize each other with respect to the production of flux
linking with the dc winding,the iron core losses it's inductive effect when
dc is applied to the center core.The other type of reactor i use has taps
coming out every row,here are the dimensions 18"x 6" X 1", soft steel will
do, laminated would be better,leave an inch at each end wind approx. 500
turns of stranded 10awg. wire.Each tap is brought out 3",windings should be
neat and tight,before winding paint and deburr,wrap with fish paper and away
you go,this sucker is very heavy and will get hot!.With this setup i can
limit current flow between 45 amps(no taps engaged)to system melt down,and
yes i've blown the mains a few times,amprobe has read 200+ amps a few times.
well good luck P.S.-----I think everything came in under $50
Bill hb-at-earthlink-dot-net