The grinding electrical spindle is a new technology that integrates the machine tool spindle with the motor in the CNC machine tool field, pushing high-speed machining into a new era along with linear motor technology and high-speed tool technology. The electrical spindle is a set of components, including the electrical spindle itself and its accessories: the electrical spindle, high-frequency variable frequency unit, oil mist lubricator, cooling unit, built-in encoder, tool changer, etc.

The motor's rotor serves directly as the machine tool's spindle, with the spindle unit's housing being the motor base. Along with other components, this achieves an integrated design between the motor and the machine tool's spindle.

Currently, with the rapid development and improvement of electrical transmission technology (such as variable frequency speed regulation technology, motor vector control technology, etc.), the mechanical structure of the main drive system of high-speed CNC machine tools has been greatly simplified, and the belt drive and gear drive have basically been eliminated. The machine tool spindle is directly driven by an integral motor, thereby reducing the length of the machine tool's main drive chain to zero, achieving "zero drive" for the machine tool.

This type of spindle motor drive structure, which integrates the spindle of machine tools, makes the spindle component relatively independent from the transmission system and overall structure of the machine tool. Therefore, it can be made into a "spindle unit," commonly known as an "electric spindle." As the electric spindle primarily uses AC high-frequency motors at present, it is also referred to as a "high-frequency spindle." Due to the absence of intermediate transmission stages, it is sometimes called a "direct drive spindle."