Re: Stepper power supplies, unregulated

Hi,

A 10K resistor really does not make much of a difference. The RC time
constant would be 10,000 times .04, or 400 seconds. 3 time constants
would be considered discharged (5% of original voltage) for a total
time of 1,200 seconds. That is 20 minutes.

Mariss

--- In CAD_CAM_EDM_DRO@egroups.com, ballendo@y... wrote:
> JMW asked:
> >Ballendo, how do you size the drain resistor?
> >Another idea is to put an LED on the capacitor as a warning, at
> >least that's what Magnetek did on the VFD out in the garage.
>
> I have to admit the "empirical toolbox" approach here. I used a 10k
> 2W resistor on a 40000uf Cap. The standard said it had to
be "below"
> a certain voltage within a certain time, and it just seemed faster
> to "parts drawer" the answer by observation.
>
> Yes, the "power" LED DOES give a "visual", but it doesn't meet the
> safety standard!
>
> Ballendo