On Monday 21 August 2017 16:19:52 Gene Heskett wrote: > On Monday 21 August 2017 15:31:41 David Berndt wrote: > > On Sun, 20 Aug 2017 18:09:20 -0400, Gene Heskett > > <ghesk...@shentel.net> > > > > wrote: > > > On Sunday 20 August 2017 03:40:56 David Berndt wrote: > > >> I'm having some issues commissioning my HY VFD. 4kw unit driving > > >> a 5hp 3450rpm motor at 30hz max frequency (temporary 2 pole > > >> motor, 4 pole motor is in the mail). Works great in "forward", > > >> but when it accels in reverse it trips out and throws an E.OC.N > > >> error. Which appears to be an over current error. > > >> > > >> I've flipped 2 leads to the motor, reversing the physical > > >> rotation and it still works great in vfd "forward", proving that > > >> the motor and mechanical aspects work in both directions. But the > > >> VFD does not. Accel times are quite conservative/slow. Problem > > >> happens about 1 second into acceleration. No clue.... There don't > > >> seem to be any relevant settings. Problem happens regardless of > > >> control method, modbus or operator panel. > > >> > > >> Unrelated, but wow, at low speeds this VFD seems to throw off a > > >> ton of interference. The symptom I've noticed is that my usb > > >> mouse connected to the PC in the control cabinet that also houses > > >> the VFD basically gives up on life if the motor is running below > > >> 15hz. USB dongle modbus was fairly impacted as well until I > > >> grounded the cable shield to the pc case. > > > > > > I had noise worse than the coaches megaphone, so I put a 20 amp > > > rated Corcom brick wall in the AC line feed. Works a treat. > > > > Any particular series you picked? Does it really matter? I assume > > some filtering, even one of the corcom filters rated as general > > purpose would be better in front of the vfd than nothing at all? > > > > >> Just to make this slighlty more on topic. Is there a config > > >> somewhere for maximum spindle RPM? With the drive configured > > >> correctly it won't overspeed the motor, but it would be nice if > > >> the software was aware of a top end for spindle speed as well. > > > > > > What are you using for an interface between the pwm (or pdm) gen, > > > I am assuming the pwmgen is in a mesa interface card?. > > > > It's just a usb to modbus dongle. So the hy_vfd user componenet. I > > realize there are ways to solve this in HAL but none of them seem to > > enforce the same way softlimits do, or I'm doing something wrong. > > I'm looking for something that will throw an error and power off the > > machine g-code sets and S command too high, or the manual control > > screen is used to set the rpm too high (ideally the interface would > > just stop increasing the spindle speed once it hits the max...). > > > > > I had been assured by the ebay critter that sold me the 1.5 hp > > > vfd, hooked to a 1 horse 3 phase motor from a 30 yo compressor, > > > that the analog input filtering was good and that I could feed the > > > analog input (0 <-> 5 volt range, it has both 5 volt and 10 volt > > > inputs) directly from the pwm generator, but I was unable to get > > > good smooth control. > > > > > > My motor is a 4 pole, and at light load it has been spun north of > > > 7K rpms. No damage if the internal fans don't throw blades, but > > > because of motor winding inductance, current draw is well under an > > > amp/phase so usable torque is an oxymoron, there isn't much. > > > Practical limit for my setup is about 140hz. From 8hz to 140hz > > > doesn't make me switch drive belts from 1st gear, no backgear. > > > > I don't plan to run a great range of motor speeds, but getting it up > > to 90hz to pickup some spindle speed would be nice if the gearing > > and spindle will take it. On the low end, if something like 20-30hz > > would be usable I'd probably be satisfied, just enough to limit > > trips ot the back of the machine to throw gear select levers. > > In my counterfeit vfd, I do have max and min frequency settings, > anything above max from the computer is limited to that, and I'd > expect you'ed be fine with a 140 HZ maz. Below the min, it shows on > the display but doesn't actually power the motor until the requested > speed is above whatever minimum you've set in the vfd. Mine does have > a modbus port, but I'd expect that to be similarly limited. > Correction since my ride has not appeared yet, my vfd does NOT have a modbuss port, not even a place on the pcb's to solder one in.
> Down on the creep end, I am not using enough low speed torque boost to > feed the motor more that its nameplate FLA*1.2, primarily because at > those speeds the motors internal fan is worthless. And I > subconsciously limit that on time to whats reasonable for motor temps > 20 minutes por so before I cop a feel, as this motor has only 40% of > the mass the 3/4 hp I took out, so it heats faster. So far so good. > :) But I've a spare just like it. One of those the price was too good > not to buy both of them deals. > > As for accel and decel times, cut them in half, try it, and keep > cutting the times until it errors, then add a second at a time until > it quits erroring. I can do a full reverse with about 1 turn of > overshoot ( I have some hal trickery that gives me the overshoot in > encoder edges ) at 200 chuck rpms. Thats quick enough to do rigid > tapping at 150 chuck revs. Since my spindle is threaded, I've made > some clamp rings to lock the backplate to the spindle flange so I'm > not worried about unscrewing a 35 lb chuck. > > Some vfd's will have a breakpoint where they switch to a different set > of acell/decel curves. You'll learn in due time where to set that > breakpoint for best results. Mine has no braking resistors, its all > dynamically 4 quadrant control but does use dc braking at low speeds. > > > > I had a mesa spinx-1 I had taken out of TLM because I was putting > > > in a 40 lb supply and one of Jon's (Pico Systems pwm-servo > > > amplifiers, great device BTW), so I pulled it out and hooked it > > > up. Works Perfect. With a bit of tuning in the vfd, I can even > > > do rigid tapping on the old grey Sheldon up to around 200-250 > > > spindle rpms. Above that and the overshoot at reversal exceeds a > > > full turn of the chuck. > > > > > > The spinx-1 needs separate fwd and rev signals, not a problem to > > > hack that in your .hal file, but yell if you need some snippets of > > > hal code, I might be able to help. > > > > > >> Thanks, > > >> Dave > > > > > > Cheers, Gene Heskett > > I'll be out of pocket at a funeral home the rest of the evening, I > hope this is some help in the meantime. > > Cheers, Gene Heskett 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
