Abstract: An electrospindle includes a motor for the movement of a tool, a pulling shaft configured to be coupled to the tool and coupled to the motor for the transmission of motion from the motor to the tool, a rotating element connected to the pulling shaft, and a joint stably coupled to the motor and having a through hole arranged to be hit on a first side by a first end of the rotating element. The joint is provided with a fitting for connection to a water supply pipe in the electrospindle that is arranged at a second side of the through hole opposite to the first side. A water sensor is interposed between the fitting and the first side of the through hole so as to detect the passage of water from the through hole in the direction of the motor.