Re: [CAD_CAM_EDM_DRO] Re: Stepper Motor Power supply Sizing.

In a message dated 5/30/2003 9:00:00 AM Central Standard Time,
davemucha@... writes:

> With chopper drives the ACTUAL current is
> different than the apparent current.
>

AND, Dave,

with the Gecko chopper drive (and I assume also with better similar chopper
drives?), it is not the CURRENT demand of the motors one should use to figure
the size of the power-supply, but the WATTAGE! I.e., if you had a 3-volt/4-amp
per coil motor, that is ONE of two coils, so you'd have a total of 24 watts
for that motor. The power-supply for that motor, alone can be a 1-amp/24 volt
supply! Sure, it'd be adviseable to make it 1.5 or even 2 amps for this
smallish size, but it need NOT be an 8-amp or 8*(2/3) amp supply! The chopping and
capacitors "integrate" the power so that close to the "name-plate current" is
eventually fed to the windings by the wizardry of the drive! NOT same as the
old L/R unipolar drives of 30 years ago!

I'd comment on the feebleness of my tiny mind, but that'd be getting OT, so,
hope this enlightens! Jan R.


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