I have a fair amount of experience with high speed spindles. And I've found that most are incapable of running much below about 1/3 of their rated speed for any length of time, and cutting anything at those speeds is certainly out of the question. If you don't believe me, start your 18k rpm spindle at 4000rpm and then check the current readout display on the VFD, and you will be shocked at what numbers you see displayed (I'd venture a guess that it would be close to about 200% of rated amps on the motor name plate).
Todd Zuercher P. Graham Dunn Inc. 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031 -----Original Message----- From: Gene Heskett <[email protected]> Sent: Wednesday, January 23, 2019 8:37 PM To: [email protected] Subject: Re: [Emc-users] 1.5 kw vfd in 6040 problems On Wednesday 23 January 2019 18:59:44 Mark Wendt wrote: > Doesn't matter. These high speed spindles are not like the motor you > have in your Sheldon. They will burn up in a short time if you run > them too slowly. > And I'll submit that it takes excess current to burn them up. Control the current below 50 hz and it will run forever, just don't expect it to throw swarf in 20 thou thick pieces even in wood. I have a 1.5 horse air cooled that running on the vfd now driving the sheldon, ran it for an hour, then overnight on the table at 20hz. I could easily lay my hand on it the next morning. But I also had the torque boost at 1.1, and the max current set to about 3 amps. Neither it nor the vfd was making worrysome heat. > But, it's your stuff. If you're willing to take the the very real > chance of either burning up your high speed spindle or destroying the > VFD by inputting incorrect parameters, by all means have at it. Been a > moderator on CNCZone for a good number of years and have seen many > folks in the spindle/VFD forum who've done just that because they > figured just any old setting would do or they tried to run their > spindle too slow. I've seen rec's that 6k revs s/b the minimum. I have aquarium lcd thermometers on the water tank and motor, and one on the driver box, but before I can log temps vs speeds, I've got to make it spin. > Mark > > On Wed, Jan 23, 2019, 18:18 Gene Heskett <[email protected] wrote: > > On Wednesday 23 January 2019 17:48:20 Mark Wendt wrote: > > > And the data plate from the motor. Incorrect settings in the VFD > > > can and will result in the destruction of either the VFD or the > > > motor or both. The settings are quite specific to the motor > > > ratings. Running the motor slower than 6000 to 8000 RPM's will > > > burn up the motor if it's a high speed spindle. You can run a > > > water cooled spindle slower than an air cooled spindle but not by > > > much before the windings burn out. > > > > > > Incorrect settings on other VFD parameters can and will destroy > > > the VFD. The manual is quite important to have setting the VFD up > > > and you shouldn't try to power the spindle up without the correct > > > settings programed into the VFD. > > > > > > Mark > > > > This seems to be defaulted to quite conservative settings. With the > > low speed boost backed off, default is 4 and probably too much, it > > should be able to run slower than that by quite a bit. I can run the > > 1hp in my sheldon at 10hz for an hour or more without getting so > > warm I can't lay a hand on it. I never exceed the nameplate fla of a > > motor at any speed. It will get warm, but the torque seems to hold > > up well enough to cut steel. > > Thanks Mark. > > > > > On Wed, Jan 23, 2019, 17:33 andy pugh <[email protected] wrote: > > > > On Wed, 23 Jan 2019 at 22:27, Gene Heskett > > > > <[email protected]> > > > > wrote: > > > > > Many thanks for any clues from someone WHO HAS ACTUALLY DONE > > > > > this. 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> _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
