Re: EDM machine

--- In CAD_CAM_EDM_DRO@egroups.com, marble here <marble_h@y...> wrote:
> My understanding on the use of Caps. I could and may
> be wrong on this ., If you use a supply of 60htz that
> will be the max that the caps will hold right ??? Now
> in Robert Langlois book he said that the min cap
> Value should be 2X the voltage but higher is ok so If
> one was to use the the 120uF 300v all would be ok ???
> The cap values would be close to the ones he said to
> use in his book such as 50uF 100uF 200uF 400uF and
> 2000uF all by 150vdcw .All the caps are to have a
> resistor 1.0 M OHM'S at an 1/2 watt . So would that
> mean that the resistor's would now have to change.???
> I have no real training here in this just learning on
> the side . Would this be the right understanding of
> the use of Caps in a EDM


Wally K. replied

If you are asking about the capasitor voltage, higher voltage ratings
are always ok.

The 1Meg 1/2 watt resistors are called bleader resistors. There
value is high enough so they do not affect the circuit operation.
When you turn off the EDM, these resistors slowly discharge the
capasitors so you do not get a shock if you touch these terminals
later. The capasitors can hold a charge for a long time with no
bleader resistor.