Start with a 226 oz in / 16 = 14.125 lb in
5 threads per inch is the same as a belt pulley with a circumference of 0.2 inches since our unit is in lb in, we need to go from a pulley with diameter of Pi, to diameter of .2 thus our final force is 14.125 * (pi/0.2) = 221.875 pounds (poundal?) force divide that by your mass of 200lb and you get 1.109 g 1g = roughly 32in/s^2 so 35.69 in/s^2 This is close to your ballpark guess of 40 Did I make a mistake anywhere? On Wed, Jul 22, 2020 at 5:24 PM Nicklas SB Karlsson < nicklas.karlsso...@gmail.com> wrote: > On Wed, 22 Jul 2020 11:29:36 -0700 > Chris Albertson <albertson.ch...@gmail.com> wrote: > > > I don't see any relation between max acceleration and max speed. > > Acceleration is determined by (1) the mass of the table and (2) the > > torque the motor can produce while speed is determined by the max RPM > > of the motor. > > Mostly agree though as torque usually depend mostly on current there will > be a resistive voltage drop at higher torque which will reduce speed at > higher torque, speed reduction is usually small. For example series > connected DC motors and induction motors made for direct will reduce speed > so there are exceptions but do not expect these are used as servo motors > anyway. > > Change gear ratio and use motor with same power different speed may change > acceleration due to rotor inertia. > > > It is very easy to buy a tiny motor with low torque that spins very > > fast. Or you can find powerful but slow motors. Multiplying the > > speed by three to find acceleration, if it works is just a > > coincidence. The factor could be 0.5 or 10. > > High torque motors usually need a gear box or will become heavy. This is > because flux and current is multiplied to get force while there is choice > between current or flux in electric motor air gap, there is an optimal > choice then either air gap area or diameter need to be increased. Magnetic > materials will saturate then flux get high enough while conductor losses > increase with current. > > > There are two whys to go. A mechanical engineer would start with a > > requirement for a certain speed and a certain acceleration. His boss > > would give him those goals and then he would select a motor and drive. > > The other way used by most amateurs is to just buy a motor that > > "seems right" and then test it to see what speed and a certain > > acceleration you can get from it. > > Not sure the boss will ask mechanical engineer about speed and a certain > acceleration and then give these as a goal to the engineer. It is common > boss read economics and contract but then it come to technical details odd > things may happen. > > > Nicklas SB Karlsson > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
