Spindle shut down during working

Hello all, I'm a newbie, I bought an used stepcraft M1000 from my friend, and Have some troubles with it during milling the working piece. 

I already replaced after some discuss on several forums :

1 - the spindle brushes

2- The AMB 1400 spindle by a new MM1000 PDI, and I have the same trouble the spindle shuts down after plunging and beginning milling. 

Yesterday, I strated to engrave a piece of exotic wood (movingui) with this settings : (please see the file attached)

V endmill 10mm 45°

cutting speed : 450

n (rev/min) : 14324

Fz : mm/tooth/rev. : 0.0095 (stepcraft benchmark)

Z : 2 tooths

Calculated Feed rate : 2722 mm/min

So I think the calculated feed rates for V groove endmill is too high??? I tested it @24000 rpm and feed rate : 150mm/min and seems working but gives me a work of 2 hours just for a little engraving... 

Some advices from your experience? 

(please see the file attached)