Linear actuator - Electro Mechanical Systems Ltd.

General motor dataDesignationDC-motorsD12BD12CD24BD24CD24CBD24CWD24CSD24DD24DBD24DSAC-motorsE220CE220CBE220DE220DBE110CE110CBE110DE110DBRecommended wiring diagram for general connection of CARwith 230/120 VAC-motorsV ACINPUTOperatingswitchCAXB/CAXCRelayF0WCSB1INSQ1KA24KA112Rated voltageVDC12122424242424242424VAC230/50 Hz230/50 Hz230/50 Hz230/50 Hz120/60 Hz120/60 Hz120/60 Hz120/60 Hz24/12 VDCmotorMSB2 SB3 1 6KA3 KA37OUT RESETSQ27KA16412KA1 10 KA2 10 KA3WCWHITERED2 RED10OperatingswitchCAXB/CAXCRelayKA2C1M76BROWNRated speedrpm7 6005 3007 5005 5005 5002 5005 5004 7004 7004 700rpm2 6002 6002 7902 7903 2503 2503 3503 350BLUEA low voltage limit switch (CAXB) can beused in connection with SKF specialelectronic control systems. As standard,motors are fitted with thermo-contactswhich activates at +140 °C.SB = operating switchSQ = limit switchKA = relayC1 = capacitatorM = motorBrush lifehours3001 5005001 5001 5001 5001 500900900900--------CalculationsLife calculationThe service life of a CAR actuator is normally determinedby the L 10life of the ball screw. In most casesthere is less wear on the worm gear and bearings thanon the ball screw.Under certain circumstances the life of the motor isshorter than that of the ball screw, however, the motorcan be easily replaced. The table, page 11, shows the lifeof various DC-motors at rated output power. Generally,the life of DC-motors is reduced when load and numberof starts/stops is increased.To calculate the basic rating life L 10of ball screw it issufficient if the dynamic load and actual stroke is known.L 10is defined as the life that 90 % of a sufficiently largegroup of apparently identical ball screws can be expectedto attain or exceed.L 500 000 p ( C ) 310 d s=S F ML 10 d s= basic rating life in double strokes i.e. a strokefrom one end position to the other and backagain.p = lead of the ball screw mm (CAR 22-2,5 mm,CAR 32-4 mm, CAR 40-5 mm).S = actual stroke (mm).C = ball screw basic dynamic load rating (N) CAR22-1 500 N, CAR 32-3 500 N,CAR 40-6 000 N).F M= cubic mean load (N).In many cases, the magnitude of the load fluctuates. Inorder to calculate the equivalent screw load, it is firstnecessary to determine a constant mean load F Mwhichwould have the same influence on the ball screw as theactual fluctuating load. A constant mean load can beobtained from the formula below.F M=3 F 13 4S 1+F 23 4S 2+F 33 4S 3+....S 1+S 2+S 3+....F 1,F 2,F 3...= cubic load (N) during S 1, S 2and S 3.... partial stroke.The diagrams show life in double strokes, L 10 d satvarious load and stroke.Example:CAR 32x500x1/D24C having a load of 2 800 N in onedirection of movement and 2 100 N in the other. Theentire stroke of the actuator is utilized.3 2 800 3 500 + 210 3 500F M= = 2 500 N500 + 500Diagram for CAR 32 shows L 10 d s= 10 000 double strokesBasic rating life L 10 d.s.L 10 ds (x10 3 )1 00050010050105L 10 ds (x10 3 )1 00050010050105L 10 ds (x10 3 )1 00050010050105CAR 22S=50S=100S=150S=200S=300500 1 000 1 500F M (N)CAR 32S=50S=100S=200S=300S=500S=700500 1 000 1 500 2 000 2 500 3 000 3 500F M (N)CAR 40S=100S=300S=500S=7001 000 2 000 3 000 4 000 5 000 6 000F M (N)1112Electro Mechanical Systems Limited tel: 0118 981 7391 info@ems-ltd.com www.ems-limited.co.uk