Gene Heskett wrote: > > > Interesting. The length of the radial portion of the bearing must be fairly > short then? The radial bearing sections are about 3/4" long, I think. These are combo hydrostatic/hydrodynamic bearings. I once had a hose blow off while drilling a hole, and waited until the drill was out of the hole to pause EMC and shut off the motor. It seemed to spin down pretty normally without the bearing air. > Or the recommended air pressure to the bearing is too low. Back > when we (tv stations) all had the 2" quadruplex vcr's, I often noted that > turning a headwheel by hand with the air off was both difficult, and draggy > like it was full of sandpaper. These are noticeably more draggy without air, but definitely not like sandpaper. Recommended pressure is 80 PSI. > >> These are >> about 2" diameter and 6" long. The motor rotor is about .7" diameter >> all the way, just a plain cylinder with a "hat" on the end for a thrust >> bearing. It will produce at least half a HP, and can go up to 80,000 >> RPM. It runs great on a VFD, although my VFD only goes to 400 Hz, so >> you get 24,000 RPM max. >> > > So it's not an air motor, just air bearings. Yes, a 3-phase induction motor. > How fast could it be brought to > speed? It can be accelerated quite quickly. As my VFD was never intended to run a motor like this, I take it easy on the startup and slowdown, and the VFD becomes noticeably warm when I run it. It stays stone cold when rnning my 1 Hp Bridgeport. I think I have it set to accelerate to 24,000 RPM in 1.5 seconds.
Jon ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
