The spindle is a machine’s heart. But just like the human heart, it is only a part of a system. Servo and ball screws, variable frequency drives, air-supply quality, can impact spindle health. If you are having unusual problems with your spindle or machine, call an expert. 

But, some problems you can diagnose.

Why is my spindle vibrating?
Excessive spindle vibrations may be due to a variety of factors such as: unbalanced collet nuts and tooling, tooling being broken or missing inserts, and tool extensions being too long for the operating speed (reference operator manual, as length becomes greater the operating speeds must decrease).

I just installed my spindle and it is running backwards
This is common with 3-phase motors with terminal blocks. Switch any two power leads and the spindle will run in the proper direction.

My spindle jerks/vibrates badly on startup and performs poorly.
This is an indication of single phasing. Verify connections at spindle, VFD, and any connectors.

I am getting an ‘over current’ or similar fault on my VFD.
Verify connections at spindle, VFD, and any connectors are clean, tight, and secure.

Verify VFD parameter settings.

If winding is shorted or insulation broken down, send to a professional for evaluation.

I just replaced my VFD and it keeps tripping out
Start by verifying that these basic drive parameters (Yaskawa) are set according to your spindle. Note: This only applies to asynchronous motors 

Verify connections at spindle, VFD, and any connectors are clean, tight, and secure.
If motor winding is shorted, send to an expert for repair.

Spindle won’t turn
Attempt to turn spindle by hand. If it rotates freely, proceed. If not, seek professional assistance.

Source: Precision Drive Systems. For information, call 704-922-1206 or visit spindlerepair.com.