Re: Power Supply Questions (Wattage?)

The resistance calculates out to 23,000 ohms.

22,600 is a standard or a pair of 11,500 would do as well.

a 1/4 watt is fine as it is only for reference, not power.

I would put the transformer, caps, Gecko's, relays, et-al in a single
enclosure. I try to keep the wiring distance as short as possible
between the Gecko's and power supply.

If you are concerned about blowing a cap and gunking up the works,
there is no reason not to enclose that in it's own enclosure. I
would install that in the main power supply enclosure and just feed
the wires out.

I would not put the power supply seperate from the Geckos. If I was
doing a large machine, I think I would considder putting individual
caps at each Gecko for a few reasons. one is that smaller caps would
be used and that would keep the remote box small.

I have a HUGE transfomer for small steppers. WAY WAY oversized and
needed to put it in an old PC tower case to fit it. (photos section-
dave's unit) you can see the 68,000 cap and 2 gecko's on a tray in
front of the transformer. I'm running 4 steppers at a total of 9.4
amps. And I am in the process of making a new enclosure with a
properly sized power supply.


Dave







--- In CAD_CAM_EDM_DRO@yahoogroups.com, "J Hamilton" <james7799@y...>
wrote:

> Related question for Dave, or Mariss, or whomever knows...
>
> My specifics are a 65VDC/8A PS driving three PacSci 252oz/in steper
> motors (Model #s M22NRXB_LNN_NS-DD) rated at 2.3A/phase, bipolar
> series, Vs(dc)=65...
>
> I figure a 22(ish)k current set resistor? Am I on track with my
> math? At what wattage per resistor?
>
> And while I'm thinking of it, since I have this huge power supply
> relative to my steppers, what is your concensus regarding putting
> the PS in it's own box (with a 27000uF Cap, bridge, fuse, on/off,
> lamp, fan, etc...) and running 2-strand up to the driver box
> (isolated 5v PS, it's own small fan, PMDX-120 board, and all the
> trimmings). I'd like to put some distance between my tired flesh
> and the Cap, if possible.
>
> Still putting this thing together.
>
> Thank you,
>
> Jim
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude"
> <davemucha@j...> wrote:
> > Hi Don,
> >
> > If you use the series connection, you wire for 1/2 nameplate
> amps.
> > select the current set resistor for 1/2 nameplate.
> >
> > Since the chopper power supply limits power as required, it will
> use
> > what it wants. typically that is about 2/3 of FLA.
> >
> > so you can size your power supply for between 2/3 and full amps.
> if
> > you ever plan on using single coil and full amps, considder

sizing

> > your power supply accordingly. even is you only use one motor,

it

> > will draw the amps required.
> >
> > I'm not sure how much line voltage/watts are used just to

energize

> > the transformer in standby. if you never use full amps, the
> > difference between the power your draw and the reserve is X

number

> of
> > watts per hour. it might not be enough to worry about.
> >
> > bottom line, set the current set resistors for the motor.
> > select the power supply for the entire system. seperate actions.
> >
> > Dave
> >
> >
> >
> >
> >
> >
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "d_bobzien"
> <d_bobzien@y...>
> > wrote:
> > > Hello,
> > > I have three Superior Electric stepper motors rated 150 oz/in,
> > 2.25V,
> > > 4.6A, 6 Leads. From what I've read these ratings are for

unipolar

> > > operation. I'll be running them from Gecko 201 drives.
> > > I read on the Gecko web site "step motor basics", if I run this
> > motor
> > > full winding (series) I should derate the amps to 1/2 of the
> > unipolar
> > > rating.
> > > Does that mean I set current limit resistor to 2.3A? But then
> when I
> > > read a few pages more about power supply it says the drive will
> draw
> > > 2/3 of rated motor current for half winding or 1/3 of rated

motor

> > > current for full winding. So for full winding that means .76A

is

> > this
> > > what I should set the current limit resistor for?
> > > Can I run the three motors off an unregulated 6A, 40VDC power
> > supply?
> > > Thanks in advance for your help.
> > > Don