To size the components of the power supply unit I follow the steps from the .pdf document Hood provided earlier.
http://campbelldesigns.net/files/power-supply-part-1.pdfI also attach a snapshot of my motors spec in case I misinterpreted something. Please note that the drivers for my motors are Unipolar and we cant change this for now. So I have 4 motors and each is 2.76VDC, 3.0A and I came up with the following:
Desired power supply voltage: 2.76 * 20 = 55.2VDC
Desired transformer voltage: 55.2 / 1.4 = 39.42VAC (This I don't understand; assuming this 39.42VAC is the household voltage where the transformer will be plugged, all households are either 120VAC or 220VAC)
Then I calculate the desired transformer current:
3.0A * 4 motors = 12.0A * 0.67 = 8.04A
39.42 * 8.04 = 316.93VA (if this is correct what will be the next transformer std size?)
Next comes the size of the filter capacitor: (I don't know where this item is located in the schematics provided by “cambelldesigns”)
C = (80000 * 8.04) / 69 = 9321.73uf (here I’m in the dark because I don't understand which current and voltage the “cambelldesigns document uses).
So the above is the 1st step in the selection of the components. If someone can check the above and answer my questions will be appreciated/