I have Roland EGX 300 and I engraving sam relief in wood.
After one hour I see that spindle motor is warm.
So, my questions is:

-How long can I set in motion my machine?

-Am I put wrong parameters for X,Y,Z axis if I choice default parameters for hard wood?

-Does motor have any protection from heating ( to turn off or something else)?

-I think that level of noise is higher when I go deeper. Is that ok?

Going deeper puts more load on the motor & bit and the noise increases.

Most motors are rated for a 55* F temperature rise at full load. Nearly hand burning temperatures. It it only feels warm, not very hot, it should be no problem at all.

Philadelphia, PA (Really Bensalem)

When you finally understand it completely... it changes.

I have spindle control on my machine (from 5000 to 15000 rpm)
What value is best for wood engraving?
Wher can I find some 3D cliparts for download for 3D engraving?

3d Vector art...

http://www.vectorart3d.com/