Gene, You need to remember that the seemingly high hp ratings of these relatively small motors is due to the very high rpms at which the ratings are valid. These 1 1/2 to 2 hp motors develop that hp at 5000 to 6000 rpm. You will have to rethink your drive coupling system to reduce that speed down to something usable especially for threading.
I am using a 2 1/2 hp treadmill motor with its original speed control on my converted jet 9 x 20. I had to use a 4.5 to 1 pulley reduction to get reasonable torque in the 200 rpm spindle range but still have about 1400 rpm available at top speed, which is good enough for me. I have plans for a shiftable double reduction setup which will be closer to 3:1 in hi and 12:1 in low. At that ratio the motor will cut anything that the toolpost will hold up to even at 150 rpm cutting a very coarse thread. I feed the speed controller through an optical isolator with PWM at 200 hz out of the parport with LCNC. Be sure to use an optical isolator. And DON'T try to compare the PWM into the isolator with the output with a dual trace scope.... Ask me how I know. I made my encoder wheel out of a CD which I painted black. It has 20 equally spaced notches with one twice as deep for the index. I used two optical interupters for the A and B quadrature and a third one set deeper into the index notch. I mounted all the interrupters on aluminum L brackets with supermagnets holding the brackets to the metal of the enclosure. I watched the Halscope while shifting the interupters around till I got the quadrature right and the index not coinciding with the A or B transitions. When all the signals looked right on the halscope I put a drop of superglue at the edge of the bracket...waited til it set then drilled the mounting screw holes through the bracket and into the sheet metal. Much more easily done than described. The 80 transitions per rev is plenty of resolution for anything I'll ever do and the pulse rate doesn't challenge the system. Cecil ------------------------------------------------------------------------------ Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with <2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
