[philbur]

Be careful. The program doesn't say but I think the calculated power requirement is at the tool, not the input. How would the program know your spindle drive efficiency.

Regards
Phil

Originally Posted by GammaWill Phil - Thanks! I see! 1W of power is consumed when cutting 1/64" deep at 12.5 IPM Most of the hobby-type brushless motors seem to be able to produce 100W easily. This cheap 3800 KV motor & ESC looks about right, and the motor case doubles as a heat sink (no carbon fiber shell on this one): http://cgi.ebay.com/3800KV-Brushless...QQcmdZViewItem Brief Specs: Motor RPM/KV: 3800 Motor Max Watts: 250W Motor Max Continous Current: 8-10A ESC Minimum Voltage: 4.8V ESC Max Voltage: 14.4V So, driving it at 5V (and at 100% "throttle") will give me 19K RPM. From the numbers above, at 5V the motor could generate a MAX of ~30W of power. So, each 1W consumed at 5V would require 200mA current. I will only need 1W, so I suspect that that running virtually "unloaded" (the cutter will not be pulling many amps @ 12IPM, and 1/64" deep passes), and even with losses through the coupling system (misalignment, friction, heat, etc.) I would be drawing WELL under 1A @ 5V, with 250mA probably being typical for my application. How's my math, guys? Did I goof up any where? ---Will