It was a quick calculation of the motor winding impedance at the frequency in question and therefore the current in the windings. Since torque is proportional to current this gives a rough idea of the torque at a given speed compared to the stall torque.
Thanks again irving, I think the only real solution here will be a servo + gearbox + driver. I'm contemplating that approach, but it's freakishly expensive, although it would mean pretty much constant torque across a wide range of speeds. If I go with a 400W servo which gives around 1.3Nm within 0-3000RPM, I can put a 20:1 gearbox on it and have 26Nm within 0-150RPM. That's well plenty for my application.
One thing I'm not 100% with servomotors, what the current requirements when choosing a PSU? is it similar to stepper motors where a 6A PSU is capable of driving 3-4 motors, or is it more like DC motors where you need a huge DC PSU to deliver the current?
By Lee Roberts in forum Machine DiscussionReplies: 16Last Post: 08-09-2016, 06:55 AM
By Jopo in forum Stepper & Servo MotorsReplies: 0Last Post: 29-04-2013, 07:08 AM
By FlightCaseCo in forum Routers, Spindles & ControllersReplies: 13Last Post: 03-04-2012, 11:53 AM
By John11668 in forum Gantry/Router Machines & BuildingReplies: 5Last Post: 31-08-2011, 05:46 PM
By Ross77 in forum Computer SoftwareReplies: 11Last Post: 28-03-2010, 02:17 AM