Re: Power supply transformer setup questions...Capa...

Bahamas, yeah right. Try writing assembly code for about 4 weeks
straight instead and see how much fun you are having. :-)

Apples and oranges are being vigorously mixed on this thread and I
guess the juice has a strange taste. Let's seperate them:

------------------------------------------------------
1, Apples) Power supply capacitor equation. This one does violence to
the differential equation "I = C dv/dt" by treating it as an
algebraic equation and solving for C. The result is:

C = I * dt / dv

At 60 Hz "dt" is 0.00833 seconds
Assume 10% ripple voltage is OK

Because the above returns Farads, multiply by 10^6 to get uF.

uF = (I * .008 * 1,000,000) / dv, giving uF = 8000 * I / dv

Finally, for 10% ripple, dv must be Supply Voltage / 10. This is the
same as multipling the numerator by 10 and using the supply voltage
in the denominator. This gives:

uF = 80,000 * I / V

Nothing empirical about it at all. Use 100,000 for 50 Hz.
---------------------------------------------------------

2, Oranges) Sizing a power supply for 1 or more drives. This depends
on the motor's rated phase current, speed and load. The required
current is independent of power supply voltage.

The 2/3 business is the maximum power supply current our step motor
drives will draw from the power supply at maximum load and speed. It
can be much less at light loads and moderate speeds. Finally, it only
applies to our drives and not anyone else's.

This is covered in detail in "The Entire Step Motor Basics
Whitepaper.pdf" available from the Support section of our website
www.geckodrive.com

Mariss






--- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude"
<davemucha@j...> wrote:

> --- In CAD_CAM_EDM_DRO@yahoogroups.com, JanRwl@A... wrote:
> > In a message dated 9/10/2003 9:56:54 PM Central Standard Time,
> > lloyd@l... writes:
> >
> > > That is VDC from the power supply?
> > > Current (I) is the amperage sum of the motors * 2/3rds?
> >
> >
> > Lloyd: Yes on VDC. The "I" is current, but I am not sure if
> the "2/3"
> > applies, here. Mariss will probably clear this up when he gets
> back from the
> > Bahamas.
> >
> >
> > [Non-text portions of this message have been removed]
>
> I agree that this is a Mariss type problem, but as I understand, he
> has been working on a flux capacitor, and as you may know, temporal
> relocation is tricky at best, and in his discussion on the

problems,

> it seems that location is a bit of a problem in that although one

may

> change location in a temporal manner, one may not find oneself in

the

> same spot, but may actually be anywhere in the space time continum.
>
> The great thing is that regardless how long it takes for work out

the

> bugs, his next post my be appear to us and appearing in a linear
> fashion.
>
> Very interesting topic.
>
> Back to the capacitors
>
> Dave