RE: [CAD_CAM_EDM_DRO] Re: Thoughts on PC Based Control Retrofit....Power Supply, advice?

What about an inductor? low impedance to DC and higher impedance to AC and
transients. Old radios used to use the dynamic speaker coil as part of the
power supply filter circuit.

-- Carol & Jerry Jankura
Strongsville, Ohio
So many toys, so little time



-----Original Message-----
From: stratton@... [mailto:stratton@...]
Sent: Wednesday, May 09, 2001 1:06 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] Re: Thoughts on PC Based Control
Retrofit....Power Supply, advice?

> admin@... wrote:
>
> > --- In CAD_CAM_EDM_DRO@y..., "Marty Escarcega" <escarcega@h...> wrote:
> > > Ok, I have found some 44VCT 11A transformers for my series I
> > > retrofit. Coupled with a 35A 1000V Bridge Rectifier and a
> > > 14000MFD 75V Capacitor for each motor, do you folks think this
> > > should be a good power supply? By my calculations, I should have
> > > about 62VDC.
>
> This should work fine. You might put a very small resistor either in

series

> with one of the transformer secondary leads, or one of the bridge

rectifier

> leads, to reduce the current surge. Something of a few tenths of an Ohm
> would probably be right. Otherwise, it should be fine. You may need a
> little more capacitance there, you will have to evaluate the voltage

ripple

> when the stepper driver is drawing the maximum current.

I wouldn't think a tiny little resistor would do anything. They do
make devices specifically for limiting 'inrush current' when a power
supply of this type is turned on. One form has a high resistance when
cold, with the resistance dropping once it warms up. I suppose you
could still get in trouble though if the unit gets switched off just
long enough for the bleeder resistors to discharge the caps, but not
long enough for the inrush limiter to cool down - so avoid excessive
power cycling.

Chris


--
Christopher C. Stratton, stratton@...
Instrument Maker, Horn Player & Engineer
22 Adrian Street, Somerville, MA 02143
http://www.mdc.net/~stratton
NEW PHONE NUMBER: (617) 628-1062 home, 253-2606 MIT




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