On Tuesday 30 April 2013 22:04:26 Steve Blackmore did opine: > On Tue, 30 Apr 2013 12:25:05 -0400, you wrote: > >On Tuesday 30 April 2013 12:06:13 Cecil Thomas did opine: > >> 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 aware of that, the toothed belt pulleys stock on the 7x means its > >turning about 8000 revs to get the 2500 rated in high back gear. I > >very rarely use it as there isn't enough torque to even cut alu 1/2" > >in diameter. > > Gene > > I'm running a no name "US made" treadmill motor as a spindle motor on an > SX3 mill, it says on the label 2.75 HP, 180VDC, Rated speed is 5700rpm. > > The brushes are 180 degreed to the armature and the motor casing, > despite this it's 1000 rpm down in "reverse" to it's normal 5700 rpm. at > 180V. It has 12 windings on the armature. It's "coggy" at less than 500 > motor rpm. It's had an encoder fitted and I tried as a servo and failed. > It generates a lot of heat and has to be fan cooled. But it's lasted > pretty well. It's done thousands of hours, had three sets of brushes and > it's due for it's third set of bearings when I get around to it. > > Works OK in it's present use linked to a KBIC-225 speed controller with > a 2:1 reduction to the spindle and it's got bags of torque at anything > over 1000 rpm at the motor. I've got the largest plug in horsepower > resistor fitted so controller's good to 16A at 180VDC. The max load I've > ever seen is 9A and I had to back off the feedrate as the machine was > struggling and complaining, but the spindle never dropped more than > 20rpm from the 2000 I'd set. I was running a 15mm end mill at the time > in AL and it got into some sort of resonant vibration - thought it was > going to bust something but it didn't. > > I like the KB SCR drives - they are pretty linear speed wise and easy to > interface using an isolated PWM to Voltage adapter. The IR compensation > works pretty good too if set correctly, little or no speed change under > load to free running. And most importantly they are inexpensive! > > Steve Blackmore
Sounds good Steve. Now, if I just had an X3. This is an x1 retrofitted by Chris's bigger tables. TBT, its a pretty good imitation of a willow tree, so tool life is short cutting itty bitty chips. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! My views <http://www.armchairpatriot.com/What%20Has%20America%20Become.shtml> Serocki's Stricture: Marriage is always a bachelor's last option. A pen in the hand of this president is far more dangerous than 200 million guns in the hands of law-abiding citizens. ------------------------------------------------------------------------------ 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
