YASKAWA E-S Series Product Manual

Contents

2.4 Selecting the Servomotor Capacity2.4.1 Example of Capacity Selection for Servomotors2-132 Selection6. Load Moving Power7. Load Acceleration Power8. Servomotor Provisional Selection Selection Conditions• T L ≤ Motor Rated Torque•• n M ≤ Rated motor speed• J L ≤ Allowable load moment of inertiaThe following Servomotor meets the selection conditions.• SGMSL-A3C Servomotor Specifications of the Provisionally Selected Servomotor9. Verification of the Provisionally Selected ServomotorIt has been verified that the provisionally selected Servomotor is applicable in terms of capacity.Position control is considered next.10. Positioning ResolutionThe electrical stopping precisionδ is ±0.02 mm, so the position detection unit is 0.02 mm/pulse.The number of pulses per motor rotation must be less than the encoder resolution (pulses/rev).The ball screw lead PB is 0.005 m, so the number of pulses per motor rotation is calculated with thefollowing formula.The number of pulses per motor rotation is less than the encoder resolution (pulses/rev), so the provi-sionally selected Servomotor can be used.It has been verified that the provisionally selected Servomotor is applicable for position control.Item ValueRated Output 30 (W)Rated Motor Speed 3,000 (min -1 )Rated Torque 0.0955 (Nm)Instantaneous Maximum Torque 0.286 (Nm)Motor Moment of Inertia 0.00629 × 10 -4 (kgm 2 )Allowable Load Moment of Inertia 0.00629 × 10 -4 × 30 = 0.189 × 10 -4 (kgm 2 )Encoder Resolution 1,024 (P/rev)• Verification ofrequired accel-eration torque:• Verification ofrequired decel-eration torque:• Verification ofeffective torquevalue:PO = = = 11.0 (W)602πnM · TL602π × 3,000 × 0.035Pa = = × × = 46.78 (W)nM2602πtaJL 3,0002602π0.10.474 × 10-4< <2(Po + Pa) (Po + Pa)Provisionally selected Servomotor rated outputTP = + TL = + 0.0350.186 (N m) < Maximum instantaneous torque...Satisfactory60ta2πnM (JM + JL)60 × 0.12π × 3,000 × (0.00629 + 0.474) × 10-4TS = − TL = − 0.03560td2πnM (JM + JL)0.116 (N m) < Maximum instantaneous torque...Satisfactory60 × 0.12π × 3,000 × (0.00629 + 0.474) × 10-4Trms = =tTP2 • ta + TL2 • tc + Ts2 • td (0.186)2 × 0.1 + (0.035)2 × 0.9 + (0.115)2 × 0.11.50.063 (N m) SatisfactoryΔNumber of pulses per rotation (pulses) = = = 250 (pulses/rev) < Encoder resolution (1,024 (pulses/rev))ΔPB0.02 mm5 mm/rev