After looking over the components, documentation, and some a gecko document. I've been able to determine that we needed only 4666 micro Farads. This was determined with the following equation:
C = (80,000 * I)/V
C = (80000 * 2.1 Amps) / 36Volts = 4666 mF
Since we are running our steppers in unipolar mode the steppers will draw 2.1 Amps. Bipolar i believe was 2.8 Amps, so we calculated it with 3 Amps and that necessitates a 6,666 mF capacitor. The hobbycnc documentation recommends using a capacitor that is 20% higher than what is requested. From these calculations we see that our capacitor is more than sufficient.
This was not the 27,000 mF that was previously thought. Also from inspection the capacitor Troy purchased is rated for 22,000 mF and 50V. So we are good! We have almost all the components we want for our power supply. We would have built it tonight, but I believe we want some fuses, power switch, and wire. We also need to design and fabricate a power supply box.
I've made some progress on the frame, i'm now toiling with some geometry issues with the frame, and trying to ensure frame stability. The issues are occuring with mounting the THK rails to T-slot bars that will inevitably have to be drilled.
http://buildyourcnc.com/supply1.aspx
http://www.cnczone.com/forums/showthread.php?t=61976
http://www.geckodrive.com/upload/Step_motor_basics.pdf (page 11)
http://www.5bears.com/cnc03.htm
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