How does the spindle motor work?

The most common question among first-time hobbyists and businesses is how a CNC machine works. Typically, high-speed motor spindle motors have windings that are 120° out of phase. After being energized, the three-phase windings each form a sinusoidal alternating magnetic field. The magnetic field rotates at a constant speed in a certain direction, and the rotational speed of the magnetic field is the synchronous rotational speed of the spindle motor. The synchronous speed of the asynchronous motor is determined by the frequency of the input motor stator winding current and the number of pole pairs of the motor stator. The motorized spindle obtains various speeds by transforming the frequency and excitation voltage of the current input to the stator winding of the motor. Since the direction of the rotating magnetic field of the motor depends on the phase sequence of the three-phase alternating current input to the stator, changing the phase sequence of the input current of the motorized spindle can change the rotation direction of the motorized spindle.

The structure of the spindle motor

Spindle motors are also commonly referred to as electric spindles, high-speed motors, engraving machine spindles, etc. The electric spindle is a set of components, the main structure includes the electric spindle itself and its accessories, such as a high-frequency frequency conversion device, oil mist lubricator, cooling device, built-in encoder, tool changer, etc.

Cooling method

The cooling methods of the spindle motor are mainly divided into air cooling and water cooling. Water-cooled spindles are generally round, while air-cooled spindles are mostly square and a few are round. Although the effect of air cooling is not as good as that of water cooling, air cooling does not need to be equipped with pumps, coolers, and water pipes, so it is more convenient to use.


Spindle motors are widely used in many industries because of their high speed and high efficiency. The above is a brief introduction to the spindle motor, I hope it can help you have a further understanding of the working principle and structure of the spindle motor, to help you in your future use.

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