Page 234 - Demo

V012024 • © 2024 Portescap. Specifications subject to change without notice.The stepper motor P430 makes 100 steps/rev. To move the load 0.50 rad with a stepper motor that has a 3.6° step angle, it will take the motor 8 steps to make this move. 0.50 rad = 28.65° 28.65°/3.6° = 7.96  8 steps of the motor needed The starting frequency equivalent to 25 rad/s is : f = (25 rad/s / 2π rad/rev) x 100 steps/rev = 398 steps/sWith 36 Vdc available in the L/R drive and 47 Ω resistors in series, the P430 can start at up to 1,700 steps/s while moving an inertial load equal to its own rotor inertia without any additional torque required. With 75% safety margin:f0 = 1,700 x 0.75 =1,275 steps/sWith an inertial load of 20 × 10-7 kg-m2 this pull-in frequency becomes:f1 = 1,275 steps/s × √(2 x 3 kgm2/(20 kg-m2+ 3 kgm2) = 651 steps/sThe problem is now solved. The working point of 398 steps/s is well below the pull-in torque curve of the P430, and no ramping is necessary to perform the desired operation.The move could be made in an even shorter time if we use a starting frequency closer to the maximum allowed: f = 600 steps/sω = (600 steps/s / 100 steps/rev) x 2π rad/rev = 38 rad/s ∆t = 0.5 rad / 38 rad/s = 13 msec0102030400.01.02.03.04.05.06.00 500 1000 2000 3000 4000 50000 300 600 1200 1800 2400 3000mNmrpmoz-inppsP430 258 013, P430 258 005 Series Torque vs Speed, Half-step ModeP430 258 013 01 @ 36V, 47 Ω ext resistorP430 258 005 01 @ 36V, 33 Ω ext resistorP430 258 013 01 @ 36V, 47 Ω ext resistorP430 258 005 01 @ 36V, 33 Ω ext resistorPull-Out Torque Pull-In Torquerpm234Engineer’s Appendix