Re: bridgeport series 1 retrofit

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:

>
>
> Bob Japundza wrote:
>
> >Guys, thanks for the responses. Sounds like having a closed loop
> >feedback system the way I described might be not worth the effort.
> >But I do plan on installing the DRO anyway. On the power supply I
> >may just add some diodes in to get the voltage drop.
> >
> You can't do that. The diodes prevent any energy returned from the
> motors to the drives from being stored safely. The small capacitance
> in the drives can't contain much energy, so the voltage quickly rises
> to damaging levels. When large motors are decelerated, they can
> return energy to the drive.
>
> Jon

Jon is right about the diodes. If you want to drop a small voltage
there's a better way to do it. Put a very small value resistor in
series between the transformer and the bridge rectifier. It has the
added benefit of reducing the peak current in the bridge and
capacitor. Even very low values will dissipate a lot of power.

Ken