On Saturday 26 May 2018 01:24:36 John Dammeyer wrote: > Is something like this equivalent to a single phase 220VAC 2HP motor? > > https://www.ebay.ca/itm/122137567723 > > Just thinking of how I'll add variable speed to my mill. Would it > even need a reduction set of pulleys or is 1:1 adequate? If the > bearings can handle it a belt ratio of 1:2 to get 6000 RPM? > > Thanks > John > Just an observation John. but a setup intended to be run as a servo, isn't exactly ideal for a spindle, and may overheat if asked to run continuously. Servo's have time to cool in between moves.
I'm not in that horsepower class, but the 1 hp 3 phase I put under the Sheldon to replace its OEM 3/4 horse single phase, with a 1.5 hp rated vfd driving it, cost me less than $200, and will run till the major caps in the vfd need servicing, about at 10k running hours intervals. I stumbled over a air compressor that had 2 compressors driven by 1 hp motors on one tank, had 40 years service time at the local horsepistol as they were remodeling & replaceing old gear. I offered the guy $50 for the two motors, and the torch was cutting rusty bolts 2 minutes later. So I got the motors for 25 bucks each. Bearings in one were noisy, so I ordered a set and put them in, going on 2 years ago now. So I've $75 in the two motors. The vfd, some sort of a Chinese fake was about $115 on ebay then, 80 bucks today. In 2nd gear in the belt system, it drives that motor from 10Hz to around 150 Hz, and can do it forever at 20Hz and up. I don't have very much low speed current boost set, but it has run for nearly 2 hours straight at 10Hz and I could still lay my hand on the motor as I've set the boost at the motors nameplate FLA. That slow, the cooling fan in the motor is not that effective At 150 Hz I get around 1700 at the spindle but its HP is in the toilet because the motor's inductance is limiting the coil current to about an amp. Thats over 4 grand at the motor, designed for 1750. The lathes spindle s/b held below 1200 according to John Knox on the Sheldon list, its plain bronze bearings. At 1700, they heat up. And all without shifting the belt. With an ER40 adapter in the spindle, I can rigid tap at 170 spindle rpms, with less than a turn of overshoot at the bottom of the stroke. Mount a chuck and the weight of the chuck slows the turnaround time though. Your HP (4 ish) in a vfd can be had from ebay now at $130+ship, a Mesa Spinx1 to interface to the vfd from lcnc is about a 20 dollar bill. That would have me scouring the junk yards for a suitable 3 phase motor. You might have to refresh its bearings but that's no big deal. -- Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
