Re: [CAD_CAM_EDM_DRO] Re: Power Supply for Gecko 320 and servo motors for 3 axis router

caudlet wrote:

>I'm not sure what the purpose of a OVP SCR across the output is for
>since under most failure conditions the primary switching components
>will shutdown rather than run wild. In most supplies if there is an
>OVP it is for the voltage that supplies the logic (+5 or +12) So it
>would never see the higher reverse voltage. Maybe if you lost the
>feedback loop to the output, but we used to design in shutdown if the
>loop feedback was out of normal ranges.
>
>

Don't bet on that. I had a VAX computer fried when a transistor failed
and the +12 V went up to 22 V.

>I think the biggest reason not to use switchers is that you just
>can't find them in voltages above 48VDC (and those are less common
>than the 5, 12 and 24 V units.) Linear regulated power supplies are
>actually less desirable for running inductive loads than switchers.
>All power supplies have to be designed for transient loads (non-
>linear current surges). The output filter section of a switcher
>takes that into consideration based on its loop charactersitics and
>the electronics in a switcher can make some pretty quick adjustments
>when the switching times are sub millisecond.
>
>

But you don't need a regulated power supply at all for powering servo and
stepper motor drives.

Jon