On Sunday 26 November 2017 22:43:27 Chris Albertson wrote: > 150F is on the hight side but not above the limit. Keep it under 200F > or 100C > > Why not reduce the current limit until it stops working then turn it > backup. Run it just above the lowest current setting that still > works. This will cost nothing. > I started it at 2.8 amps, but it couldn't move the table a whole turn in 2 minutes w/o stalling. The table is pulled down tight and to really free it I have to inject around 90 psi of air into a groove I've machined into the mateing faces of the base to table. At 3.8 amps, it can move reliably at about 35 degrees a second, several times faster that at 2.8 amps. It also suffers from resonance stalls, and I did have a damper on it, but used that damper on TLM's Z motor, doubled its speed. I need to locate some more of that shafting and make more of that damper. A summer days project for the bigger lathe now.
What I intended when I fixed it for air injection, was to put a solenoid valve feeding it with shop air, that I could energize before moving the table, and shut off when it had reached to new position. But that has turned into a search for a suitable air valve at an affordable price. Plus I keep trying to think of some way to keep the air from blowing out the bearing in the bottom, taking the grease with it. Its a good leak, starting the air compressor in 5 to 7 seconds. > If it ever fails you might want to replace it with something else, A > couple options.. Starting with a triple stack 470 oz/in for starters. Which is sorta ridiculous because its only a 4" table. The motor, and the worm are at a strange angle and is always in the way regardless of how its bolted to the mills table. What I need is a 5" table but haven't stumbled across one thats not $300, before I put a motor on it. Someday, before I miss morning roll call I hope. :( > > 1) What you may need to do is find a motor that is a better match to > the load. Then it can run without having to work very hard and run > cooler. This is direct drive, worm is 90/1. So even at 36 degrees a second the motor is only doing 10 rps or less. So yes, a planetary 10/1 might be an improvement. Or a 5/1 belt drive, turning the motor around so it doesn't stick out as much. All have been thought about but no chips have been made yet. Generally, it works except for the backlash, it made #25 chain sprockets with teeth too wide to fit between the rollers because the tool was pushing it one way or the other. Which is variable because the bull is eccentric, so it varies. Mapping that would need a home switch to align the map. Then whats needed next? So there is, with this one, a definite point of pouring time and money down a very poorly made in India rat hole. Need a better table for the next step. A 6 incher is about all I can pick up. The 8" chuck on the sheldon I can move, but mounting it needs props, I can't hold it up long enough to screw it on. I need to make a bed fitting sled. > 2) The other option, more expensive is the now closed loop steer > motors. These use an encoder in the stepper motor that connects to > the driver, so you'd need to replace both bt it uses only enough > current to make motor step. They run much cooler I've looked at those, but pushing $300/axis is just too much. If I was making money, yes, I could pay for them, but I'm not, this is pure hobby. Thanks Chris. 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
