In a dimly lit room, you may well glimpse sparks through the ventilation grids at the back of your Cook Expert.
These are a characteristic of the sturdy (30-year warranty) commercial-grade motor we have chosen to withstand the wide variations in speed.
They are entirely normal and nothing to worry about, and certainly do not affect the operation, efficiency or durability of your Cook Expert.
However, if you are concerned please contact our customer care team.