Re: [CAD_CAM_EDM_DRO] How to select power supply???

Hey Jon~!
Thanks for the help -
Questions interspersed.

From: "Jon Elson" <elson@...>

> > Do you choose the power supply first, or the driver boards?
>
> Choose motors first (in general), then choose drivers that can
> power the motor properly, then choose power supply to suit the
> needs of the driver.

The motors I got were the specs I posted.
So I look for a driver now, huh?
I haven't seen a chopper driver for something with these specs,
but that's part of the problem. ( I don't know the voltage rating of them)

> > Do you *add* all the amperages for *each* motor?
>
> No. You need to make some sort of computation based on actual
> power draw of the motors. Since almost all new drivers are swtiching

type,

> current into the driver is much less than current in the motor windings.
> The current draw rises as motor speed increases. But, in general,
> the drivers will rarely draw current equal to the rating of one winding,
> assuming a sufficient DC supply voltage is chosen. Even if this
> current is drawn, it will be for short bursts. Unregulated DC supplies
> can supply peak power above the rating point for short periods.
> Also, a slight dip in DC voltage will not affect the drivers.

When you say "switching", are you saying that the driver is turning off and
on,
or that it's acting like a relay, and thus not handling the voltage and
current itself?
Sorry, trying to learn.

> > (for me adding three motors?)
> > And how can I tell at what voltage these are safe to run at?
> > 12V or 48V????? Or somewhere in between?
>
> This is mostly determined by the specs of the drivers. Some can
> handle no more than 35 V, some can go to 80 or so. The driver
> limits winding current to whatever you set it to, so you don't really
> need to worry about DC supply voltage versus the motor voltage
> rating.

Sorry, I'm pretty ignorant in the electronics area.
(probably other areas as well)
Are you saying that drivers have an adjustable current setting
so I can tailor it to the motor specs?
The motors are rated at 3.5A uni, and 5.0A bipolar.
So I should look for a driver that is 5A capable (or rated) ?

So, I should look for a power supply that is capable of supplying the
amperage, and just go with a "in the ballpark" voltage?
If the motors are rated at...let's say 5A, and it is possible that all three
motors will be
engaged at the same time (three axis move) wouldn't that draw 15A
theoretically?

> > I have *some* schematics available to me,
> > but haven't been able to make heads or tails of them.
> > Let me know what I should be looking for on them, maybe?
>
> Schematics of what, motors, or drivers? Without comments on them,
> a raw schematic may be of little use. You can't tell what voltage or
> current it can handle just from the schematic, unless it says so in
> words, without looking up the component ratings in databooks.

I think both.
The schematics I got are found here:
http://sisp.net/~sclark/SIGMA%20STEPPER/
The guy that sold them to me posted them.
Being this ignorant, I can figure out *some* of what it's saying,
but not much, and definitely don't see anything about voltage.