Page 233 - Demo

V012024 • © 2024 Portescap. Specifications subject to change without notice.Examples of DMM Stepper Motor CalculationsExample: Positioning with a DMM Stepper MotorFor this application we are looking for a Stepper motor for an intermittent duty application. The applicationrequirements are: Available voltage: 45 Vdc Available current: 2 Amp Motor operating point: 0.5 rad [θ] desired motor position 20 × 10-7 kgm2 [Jload] motor load inertia on the output shaft 20 msec [∆t] desired move time 40 °C [Tamb] operating temperature Intermittent operation Motor dimensions: 68 mm maximum allowable length 35 mm maximum allowable diameterL/R Driver - No Gearbox - No Ramping AccelerationLet us first see whether the move can be accomplished with a simple L/R drive not featuring ramping acceleration. In this case we need to check whether the motor can start at the required speed and load inertia.We consider the speed profile to be rectangular with constant speed: Speed = ω = 0.5 rad / 0.02 sec = 25 rad/s nmotor = 25 rad/s × 60/2π rpm-s/rad = 239 rpmThe figure shows the pull-in and pull-out torque curves for the P310 motor. We will use a simple L/R drive which provides 7 Vdc in full step mode. Since no ramping is provided (constant speed), the pull-in torque curve shows a maximum starting speed of 800 rpm when accelerating an inertia equal to the motor inertia and without any additional torque (friction torque is zero for example). With a safety factor of 75% the maximum starting frequency is f0 = 600 steps/s. The inertia of the P310 is 0.86 kg-m2 but we need to accelerate 20 kg-m2. Therefore the maximum starting frequency f1 to move this load is: f1 = f0 × √((2 × Jm )/(Jm + Jload)) f1 = 600 steps/s x √((2 x 0.86 kg-m2) / (20 kg-m2+ 0.86 kg-m2)) = 172 rpmAs a result, P310 with a simple L/R drive would not be able to suit the requirements.0.01.02.03.04.05.06.07.08.09.00.00.20.40.60.81.01.21.40 400 800 1200 1600 2000 4000 6000 8000 10000120000 400 800 1200 1600 2000 4000 6000 8000 1000012000mNmrpmoz-inppsP310 158 005, P310 158 170 Series Torque vs SpeedP310 158 005 @ 45, 0.5 AP310 158 170 @ 7VP310 158 005 @ 45V, 0.5 AP310 158 170 @ 7VPull-Out Torque Pull-In Torquerpm233