> -----Original Message-----
> From: [email protected] 
> On 2021-02-13 18:10, John Dammeyer wrote:
> > Friday night I put everything back onto the mill to make sure that
> > with all the cabinetry and wiring changes (including a new Knee Motor)
> > that I hadn't broken anything.
> >
> > Everything works as this video demonstrates.
> > https://youtu.be/I6lvnYhlez4
> >
> 
> Nice demo, and impressive speeds.
> 
> What is the max speed of the spindle?
> 
> Marcus
The 3 pulley combination with single phase motor was 2950 RPM and from what 
I've read you don't really want to push the stock bearings past that.  

The Bergerda 1.8kW Servo is 3000 RPM with two custom pulleys for 1:1.  I can 
also get about 1.5:1 with a slightly different pulley set to increase torque at 
lower speeds if I need it.  So far with what I've done I've not seen major 
loading.  I'm using PWM to a small far easy 0V to 10V module which limits low 
speed to 100RPM and does go to 3000 RPM.

When I had the setup on the bench this week I ran a motor with step/dir instead 
of PWM.  Easy with MACH3 because you just change a check box for PWM (1kHz)  or 
STEP with appropriate tuning for max RPM.  At the moment impossible using the 
MESA 7i92H without running different wires from the second parallel port.  Or 
going through the process of reprogramming the existing PWM pins to have a 
step/dir module instead which I don't know how to do.  Be nice if the FPGA 
firmware had a few parameters that could be set from the HAL file to select 
either PWM or Step/Dir.  I'm using the stock MESA 7i92_C11Gx2D.pin file.

The technique for stepping under WIN-XP parallel port does create considerable 
jitter and inaccuracies.  I found when I set up to create a step rate for 3000 
RPM after 20 or so seconds the servo would fault with a following error.  The 
motor itself is limited to 3000 RPM so if you exceed that step rate then 
eventually it can't keep up.

Setting the step rate to give me 2980 RPM (as indicated on the Bergerda LED 
display) no longer created the following error.  I could probably tweak it 
closer.  I did not try moving the USB SmoothStepper over from the CNC router to 
see if it was more stable.  Don't care really.  I seem to boot into LinuxCNC 
more often then MACH3.

Under LinuxCNC I expect with the MESA once I've assigned HAL Pins configured to 
use one of the step/dir modules that the step rate for 3000 RPM will be very 
precise. But even then I'm probably best to aim for 2950 RPM. 

Oh and I think the other reason it wouldn't be a good idea to go above 
manufacturers recommended 2950 RPM is that when I tighten the quill clamp the 
bearing noise in the spindle changes.   I don't know if other mills do this but 
it's certainly not encouraging.

John




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