I have been working on this problem for a while now. I hope someone else out there knows what's up:

My machines "ZERO" spindle speed is not always registering with relay CRZS.

When this happens, here are the side effects:

1. I have no clamp/unclamp of the chuck
2. Reset does not fix it.
3. The spindle will not restart
4. Hi/Lo range will not toggle.

If you keep trying G97S500M03 in MDI along with a manual "SPIN" of the chuck, sometimes the spindle will come to life.

I know it is the ZERO SPEED circuit. The problem is I have had problems tracking the source down.

Here is what I know:

1. It's not the spindle encoder because I unhooked the AMP connector and the problem still exists.
2. I checked relay CRZS and installed a new realy with a led indicator.
3. Hydralic system is working properly.

Other than the encoder, how does this machine know that the spindle is moving? I can't see any sensor or feedback unit anywhere near the headstock either up front or behind or below. Spinning the spindle by hand while it's dwelling on the M03 does not always work, but when it does you can tell it has a 1 to 1 effect on the spindle coming on. It's not just by chance.

My local Mori Dealer has nobody to service these old machines. He is the one that led me down this ZERO speed path. From what I have seen, I think he is right.

Has anyone ever had this problem? And does anyone know about Yaskawa Spindle drives and how the ZERO speed works?

1980 SL3B Yasnac 2000G (SLD)

Thank you!

Yes in the spindle amplifier there is a zero speed signal thats habilitaes the CRZ. This relay sometimes failed or maybe you have to check the wire.

Carlos

Check for an LED on the spindle drive that has an abreviation next to it that might sound like Zero speed, or ZSP or something like that. Some spindle drives have it not sure if this one does. That will tell you for sure if the signal is comming from the spindle drive.

What is the part number on the spindle drive

IF ITS a Yaskawa 626 drive, the spindle zero speed relays fail a lot. When you have the problem, tap on the small can relays on the SDU with the back of a screwdriver. Tap, not hammer!