Re: [CAD_CAM_EDM_DRO] Off topic, inverters / rectifiers

A few are thyristor controlled, like the Magma from ESAB.

John

> I have never seen a Mig that wasn't DC and all used a rectifier to get

there.

>
> Garry
>
> > > If that's what a rectifier does then how is the inverter
> > > different? I have seen bridge rectifiers and understand they use the

four

> > > diodes in that 45 degree pattern to cut the waveform up. I'm sorry

it's off

> > > topic but you are the people I'd expect to know about this.
> >
>
> > An "inverter" welder has a big recitifer that converts input power to
> > about 340 V DC, and then has a set of power transistors that chop the
> > DC up into roughly square-wave AC at 25 KHz or so. This is then run

through

> > a roughly 20:1 step-down transformer and a full-wave rectifier.
> > This then produces the DC output, which is electronically regulated for
> > proper voltages and currents. For "square-wave" TIG, this is then
> > followed by an electronic switch that flips the polarity of the

electrodes

> > at a low frequency (a few hundred Hz) for the required duty-cycle
> > to keep the electrode clean.
> >
> > So, an inverter welder is quite different from a rectifier. The other
> > difference
> > is that the power transformer, operating at 25 KHz instead of 60 Hz, can
> > be almost 400 times smaller and lighter!
> >
> > Jon
> >
> >
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