JMC 2.6KW AC SERVO SPINDLE NOT SOUDING RIGHT

[RJS100]

My friend Bruce is converting a PM833TV that almost exactly mirrors mine. We are both using a JMC 2.6KW AC servo for the spindle motor. Both are geared exactly 1.8:1 to yield a top speed of 5000 rpm. Both systems use the same 72t & 42t HTD pulleys and a 25mm wide HTD timing belt.

Both servos were ordered directly from JMC. The only difference is that his model a more recent model of the same one I purchased. JMC says the only difference between the motors is that the height of the motor changed by a few millimeters. Other than that, they are supposedly the same. We are using the same servo driver.

Bruce programmed his servo using the same programming as shown below. When I run my machine, I can run up to 4500 rpm and the system is fairly smooth and quiet. You can have a conversation while sitting next to the mill. At 5000 rpm, it gets a little on the louder side. To be expected.

When Bruce runs his mill, it is so loud he needs air muffs and does not sound like it is running smoothly. Here is a video demonstrating this:

https://www.dropbox.com/scl/fo/cvsd7uum ... s68rg&dl=0

Any idea as to why this sounds so rough would be appreciated.

Thanks... Richard


Servo Programming:
P01-01 to 1: Speed control mode
P06-09 to 23 : Speed analog command direction input on DI5
P04-14 Acceleration time 200ms/1000rpm for direct (belt) drive
P04-15 Deceleration time 200ms/1000rpm for direct (belt) drive
P06-40 Speed analog instruction gain 10 rpm/V - Set to 285 to match to get max rpm of spindle 5070 rpm
set P06-24 ---> Set to 0
Bench test with motor connected to timing pulleys etc. with all load attached.
run AF_J-L and record the measured moment of inertia ratio and write it in P01-04 (2.73
Changed parameter 01-03 from default 13 to 9 to stop knocking from spine shaft drive.
This parameter works with 01-02 which remains at default 1

[suntravel]

Did you run the servo not connected to the spindle and is it quite?

For me it sounds like a problem with the spindle bearings, or a loose drawbar.

Uwe

[RJS100]

Thanks Uwe. He is using a power draw bar, so the drawbar is being pulled tight by a stack of Belville washers. I will check that there is adequate preload on the washers. Is that what you were thinking?

We will also pull off the belt and try with the servo motor only. It almost sounded to me like either the spindle bearing is preloaded adequately or the bearing on the servo motor are no good.

Richard