RE: [CAD_CAM_EDM_DRO] Re: POWER SUPPLIES

I translate this to my original statement that for beginners linear
supplies are the way to go. They just work without requiring any
additional knowledge of adding caps for stiffening the output or active
engergy dump systems.

Tim
[Denver, CO]

> -----Original Message-----
> No, the switching-type stepper drivers draw current in sharp
> pulses. Swithcing power supplies often have small capacitors
> inside, and can accomodate current fluctuations of so many
> amps/microsecond. If the current transient has greater slope
> than that, the servo regulation loop will either become
> unstable, or the supply just can't keep up with such a
> transient. Therefore, to keep things stable, you really need
> to insure that the current transients are within reason. A
> modest capacitor will assure that.
>
> Some stepper and servo drivers also allow energy to be
> extracted from the motor and returned to the power supply.
> Under this condition, either a large capacitor bank or an
> active energy dump system needs to be provided to absorb that
> energy. If not, the bus voltage will rise until either the
> power suppy triggers its overvoltage protection crowbar
> circuit, or the driver is destroyed.
>
> Jon
>
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/