Re: [CAD_CAM_EDM_DRO] Re: CNC power supply question

bull2002winkle wrote:

>
> The only thing I have not seen that you may want is a bleeder resistor
> across your filter capacitor to discharge it when power is turned off.

Definately not! While bleeding the cap is an ESSENTIAL SAFETY thing to
do while building up the (unregulated) power supply (and I provide a
temporary resistor in the kit for that purpose, for working around or
trying to hook up a gecko to a charged capacitor is exceptionally dangerous
to life & limb & Gecko), ... bleeding a big electrolytic down to 0 volts
over the long term will lessen its life considerably (from perhaps 15-20 years
down to perhaps 3-4 years).... so says the manufacturer of my monster
(68,000uF 80V/100V capacitors).

In fact, when the capacitors arrive from the factory they all have a
'storage voltage' on them of 3 to 4 volts.

When the capacitor is hooked up to my three G201 Geckos, and the PS is powered
OFF, the Geckos drain the capacitor down in about 2 minutes, but ONLY down to
1.4 volts where I presume the Geckos transistor junction blocks further drainage.

This is a perfect symbiotic circumstance.... the cap is drained in a short
time for safety, the Gecko's LED goes out to signify the drainage to 1.4V
is complete, but the small 1.4 Volts remains on the cap to prolong the
capacitors life.


cheers
Doug Fortune watch for -> 2.5KW 70VDC supplies in development
http://www.cncKITS.com (for lathe & mill servo spindles).




































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