Re: [CAD_CAM_EDM_DRO] Power Supply and Capacitor Questions Help!!

You will want to connect all three capacitors in parallel. Then use one
bleed resistor.

You cannot parallel the outputs from the three bridge rectifiers.

Bob Campbell

----- Original Message -----
From: "rogersmach" <rogersmach@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Thursday, September 04, 2003 9:40 PM
Subject: [CAD_CAM_EDM_DRO] Power Supply and Capacitor Questions Help!!


> Hello,
>
> I'm in the process of assembling a CNC control consisting of the
> following: 4 axies, 3-40 in/lb DC brush type servo motors that are
> rated 40v/K at 2500 rpm 13.7 amps maximum current. 1 servo motor for
> the 4th axis which I have not obtained yet but will be smaller. I'm
> using Mach2 for a control program. Bob Campbell's Sound Logic
> breakout board for Mach2. I'm using Gecko 320 drives. I'm using a
> power supply from the old control of my bridgeport which has 4 set of
> output taps on the secondary and their voltage values are: 1 set at
> 31 volts AC, 1 set at 10 volts AC, 1 set at 4 volts AC and the other
> set read 0. In talking with Mariss at Gecko drive (brilliant man,
> hate to bother him), he suggested that I use about 60 volts DC with
> his drives. Which would reduce the speed with little effect on the
> torque (if I understood him correctly). And I would need a 100 volt
> DC capacitor rated at 45,000 macrofarad or greater. I could not
> locate a cap with this value and had to settle for 3 100 volt
> computer grade DC caps at 15,000 macrofarad. Question: Can I wire
> these 3 capacitors in series to achieve the same Macrofarad value? I
> intend on using a 1.2k 5 watt bleed resistor on each. Next Question:
> Would it be possible for me to run the 31 volt taps through one
> bridge rectifier and 10 volts through another bridge rectifier, wire
> them in parallel to get my output up to around 41 volts DC? Is it
> possible to change the configuration of the primary side and get
> higher values? I intend to use the present supply temporarliy to get
> operational, then acquire a more adequate supply later. At the 31
> volts it appears to be pushing the X axis (servo running directly off
> of bridge at 31 volts DC without capacitor and a 2.5:1 reduction)
> about 30 inches/min Id like to get it around 70 or 80 inches /min
> rapid. Any more than that is unsafe on a bridgeport. Any input on my
> inquiries would be appreciated.
>
>
>
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