RE: [CAD_CAM_EDM_DRO] How do i pick out a transformer?

> -----Original Message-----
> To get 100 vdc output from a toroid, the secondary would need
> to be 71.42v. Once run through a rectifier and capacitor, you
> will have 100 vdc.
>
> Most toroids are rated in volt/amps (VA). Multiply 72 volts x
> 20 amp = 1440 VA

But remember, that if you get a 71.42 v transformer with 110 vac input
you are likely to blow the drives from over voltage the first time that
the mains spike any higher. You also have to be concerned that any back
voltage from a drive may drive the supply voltage over the limits.

Far safer to give some leeway and aim for a 85 - 90 vdc supply and have
some margin. Your performance will not be significantly impacted and you
will have a system that is reliable for years. Remember, machine tools
need to be designed like tractor trailers so they work reliably for
years with just normal maintenance. Not like race cars that go blazingly
fast for the event then need a total rebuild.

Tim
[Denver, CO]
Visual Mill 5.0 Basic at a price too low to post!

Sherline & Taig products at Deep Discount
Mach1 & DeskCNC with credit card ordering
www.KTMarketing.com/Sherline
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