'95 4020HT, what happens if a spindle belt breaks?

[Wade C]

Just learning and thinking about possible catastrophes. (I callem cat-a$$-trophys)

1995 Fadal 4020HT with 88HS (1400-4 board) control, 10k spindle, rigid tap, TSC.

I could see a couple different things happening... and I realize the damage that occurs is variable depending on whats in the spindle, and whats youre doing... but my question is really more about what the control sees, and then does.

So, for the sake of an example... No tool in the spindle, not cutting anything, running a program for the fun of watching the machine move on its own .... and the spindle belt breaks. Maybe it wedges in and stops the spindle, or maybe it coasts down.

Does the control monitor the spindle speed and error out if it falls noticeably below the specified speed?
Does the control only monitor the spindle motor via the drive, so as long as the motor itself is spinning, the control thinks all is well?
Does the control notice a drop in spindle load and error out?
Or, does it not pay any attention and just keep on trucking through the program with the spindle off?


Just trying to wrap my head around what the control might do. I guess some of it has to do with planning maintenance, change a belt when it breaks, or a more proactive approach of changing it every X number of hours of spindle on time.

Thanks in advance.

Wade

[denmar]

Control monitors spindle rpm through a Hall effect switch; spindle stops; Error: Motor overload; spindle fault; If no belts; spindle runs for a few secs and faults out. Want to kkep running the program? clear the error, delete all M3 and Sxxxx from the program.

[Wade C]

Thanks so much!

I was hoping that the control watched the actual spindle rather than just the motor. Im used to lathe programming in IPR, so if something happens to the spindle belt or encoder belt, it doesnt completely kill things... crash kinda... yeah, but not as major catastrophes. So I was curious how the Fadal handled a broken belt.

Puts my mind at ease a little... in a weird way.

Wade

[denmar]

there' a magnet mounted on the spindle pulley; everytime passes under the Switch it counts de rpms, send to contoller card, to Inverter; Machines with Encoder inside spindle motor comunicates with both, card and Inverter.

[Wade C]

Is it a case of my machine would have either the hall effect on the spindle pulley, or the encoder on the motor? or might have both?

I do know there is an encoder on the top of the spindle motor, under the cover and fan. But have no idea if there is something on the spindle itself or not, have not had that part apart yet... though guessing when I replace belts Ill know more... or maybe when I get in and do belleville springs.

THanks again
Wade

[denmar]

iF HAS RIGID TAPPING; HAS TO HAVE ENCODER, HALL EFFECT SWITCH ALSO WORKS FOR THE SPINDLE ORIENTATION; REPLACING VELLVILLE SPRINGS ONLY IF TOOL IS LOOSE OR
WON'T GRAB IT.