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Re: Electrical Noise
开云体育I had a KL34H280-45-8B 4.5 N.m. drive but found I couldn't run it very fast. ?I upgraded it to a? KL34H2120-42-8A which static torque is 8.4 N.m.? But it's all about speed isn't it. ? The math with me thinking out loud is as follows: 0.25" per rev of Z Knee motion (or 4 revs per inch) 3:1 reduction with toothed belt. Gecko microstepping driver which is 2000 steps per rev or (if it were half steps 400 steps per rev). ? So 2000 * 3 * 4 = 24,000 which is what I have in the MACH motor tuning screen.? And if it were half steps then 400 * 3 * 4 = 4800 steps per inch. ? Max speed is set to 25 IPM.? ? Work that backwards and it's 10kHz step rate. Ie. 10,000 steps/second is 600,000 steps per minute (300 RPM). And 600,000 steps per minute divided by 24,000 steps per inch is 25 inches per minute. ? If it were half steps then it's 2000 steps/second and the torque curve puts that at 4.5 N.m which matches the smaller motor and that I couldn't get that moving past about 12 IPM because then torque fell below 4 N.m. ? This is with both the vise and the rotary table sitting on the X table.? ? The torque on the bigger motor falls off almost linearly so it's one half the torque at 4000 steps per second verses torque at 10000. ? ? The AC Servo I have is 1.27 N.m at 3000 RPM with a much higher peak rating and if it were reduced to 300 RPM I'd have 12.7 N.m or 3x what is needed.? I would really just need to add an extra 3.5:1 to bring it down to about 850 RPM which scales axis speed up now to 70 IPM. ? Or get a bigger servo.? One that is about 2.5 N.m at 2500 RPM and change the reduction from 3:1 to 6:1.? (120T pulley and 20T pulley). ? That gives me 104 IPM with torque at the hand crank shaft at 15 N.m compared to the stepper 13.5 N.m at only 25 IPM. ? Assuming I've done the math correctly. ? So if I want the speed for peck drilling… ? John Dammeyer ? ? From: [email protected] [mailto:[email protected]] On Behalf Of dave via Groups.Io
Sent: January-29-20 10:19 AM To: [email protected] Subject: Re: [MachCNC] Electrical Noise ? My heavy Z axis used to struggle with a big Nema 34. I swapped it out for a Nema 23 4.5Nm and it flies now.?? ? Dave ? ? ? Sent from my Samsung Galaxy smartphone. ? ? -------- Original message -------- From: John Dammeyer <johnd@...> Date: 29/01/2020 5:44 pm (GMT+00:00) Subject: Re: [MachCNC] Electrical Noise ? And mine is this one: ? For all I know this is causing a problem during homng. E-Stop, Fault, ERR/RST, and "Charge Pump" timeouts turn off all outputs without assistance from host software ? If for some reason the Fault or E-Stop inputs have a spurious pulse then I could see it stopping on homing Z. ? ? Or if the MACH3 Homing Z software does something odd occasionally with the charge pump this would also cause issues.? And some sort of WIN-XP issues could cause the charge pump to vanish shortly after booting WIN-XP. ? That would also explain why the problem never shows up on LinuxCNC with the parallel port or the MESA Ethernet 7i92H.? If it comes back I may just 'borrow' the USB Smooth Stepper from my CNC router.? Another option is to set the dip switch on the PMDX-126 to disable Charge Pump. ? ? May not be electrical at all. ? John ? ? ? From: [email protected] [mailto:[email protected]] On Behalf Of dave via Groups.Io ? Hi Spencer ? No.? Some are straight though... ? ? ? ? But read the spec on this one... ? ? ? Dave ? Sent from my Samsung Galaxy smartphone. ? ? -------- Original message -------- From: spencer@... Date: 29/01/2020 5:14 pm (GMT+00:00) Subject: Re: [MachCNC] Electrical Noise ? I have been following this thread but not carefully because I didn't think I had a problem. Now I am thinking that some minor drift I have over time could be missed steps not mechanical as I thought.? ? Is there any problem setting the debounce time as 10 or 20 us?? if this is input debouncing then what signals are being considers as noise sources, limit switches? there is no position feedback? ? also, aren't all break out boards opto issolated? ? ? ? Best regards, Spencer Chase ? ------ Original Message ------ From: "dave via Groups.Io" <qconvers@...> Sent: 1/29/2020 6:00:22 AM Subject: Re: [MachCNC] Electrical Noise ?
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