[Craig1971]

Hi i hope some one can help. I have a Hitachi seiki vm40 with Seikos control, it has Mitsubishi 6000rpm spindle motor and drive. It will not go above approx 2900rpm. No alarms, no load on spindle, no noises. Control working perfectly otherwise. Can some one give me some helpful advice?
Thanks in advance,
Craig.

[BattyZ]

Do you have a winding's selector? Sounds like you are not getting into the H windings? Also, check the drive parameters? Did this happen all of a sudden?

[cncmakers001]

Hi i hope some one can help. I have a Hitachi seiki vm40 with Seikos control, it has Mitsubishi 6000rpm spindle motor and drive. It will not go above approx 2900rpm. No alarms, no load on spindle, no noises. Control working perfectly otherwise. Can some one give me some helpful advice?
Thanks in advance,
Craig.

If it is using frequency inverter, then you can check its setting for highest speed, is it match with 6000rpm speed?
Or you can check the electronic gear ratio setting.