Evening all,
Has anyone run a 3 phase welder from a rotary single to three phase
convertor?
It seems that secondhand 3ph TIG sets are much cheaper and more
abundent than
single phase ones. I have a convertor, which is currently only used to
run the mill, to the 540 will be wired upto it in due course.
cheers
Dave
according to the isomatic website ..sellers of three phase rotaries
Boosters are designed to run induction motors most efficiently.
Welders can also be operated but the converter size should be chosen
to be larger than the welder input power by 50%. If no power rating is
shown then multiply the welding current by 50 for A series converters
or by 30 for D series converters. The result will be the converter
power rating in Watts for 100 % duty factor, often misnamed duty
cycle.
so a 180 watt welder needing 16 amps would need 24 amps ..or 8 hp
rotary converter if i got my sums right .
all the best.mark
You can run some three phase wound transformer tigs and migs off
single phase
but you only get half the power .
Done it with mine, a cebora special uno 200 amp tig
Just a mater of moving a few wires around under the lid
all the best.mark
Hi,
In my opinion you could use a smaller converter, as long as it's got a
large flywheel to operate as an energy store. Often wondered about
this. An electronic converter is a massive nono just to state the obvious.
You can do a lot with a large flywheel energy store. Would it be easy
to add a flywheel?
Rob.
Although it's counterintuitive, the added mass of a
flywheel does not improve (reduce the effective source impedance)
the performance of a rotary converter. Some rotary inertia is
needed, but only enough to smooth the cycle to cycle torque
variation. The inertia of the motor rotor is normally ample.
Static phase converters rely on start and run capacitors
and the motor inductance for the phase shift mechanism. These
will not work on a transformer/rectifier load.
Electronic VFDs will drive a three phase transformer
rectifier load if DC output is the only requirement. However they
will fail miserably if there are control circuits that need a
sinusoidal supply waveform.
Jim
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