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In comparison to other motor types, stepper motors have noisy, but they are renowned for their accurate placement and control. This article will include potential causes of noise from stepper motors and offer solutions to that problem.
Because they are mechanical devices, stepper motors can produce a lot of noise when operating. The rotation of a stepper motor occurs in discrete steps, and the transitions between these steps can generate vibrations and noise. The mechanical structure of the motor can resonate, which can amplify the noise, and the variations in the motor's magnetic field as it advances from one step to the next are the actual culprits here.
Another potential source of noise in these devices is the drive type employed to regulate the stepper motor. The operation of some drive systems, including full-step drives, might cause them to produce more noise than others. For instance, a buzzing or humming sound might be generated by full-step drives due to the constant switching of the magnetic field.
How loud a stepper motor is when running is conditional and motor type dependent. People have compared the sound of a stepper motor to a high-pitched screech, a hissing sound, or even a tyre deflating. The typical range of frequencies that humans can hear is 20 Hz to 20 kHz, while the sweet spot for human sensitivity is 2 kHz to 15 kHz. As a rule, hybrid and permanent magnet stepper motors are less noisy than variable reluctance stepper motors. It is possible to classify the noise produced by a high torque stepper motor as either electrical, mechanical, or magnetic.
Ferromagnetic materials exhibit magnetostriction, a phenomenon that causes magnetic materials to expand or contract when subjected to a magnetic field. As a result of the magnetic field, Molecular dipoles, and magnetic field boundaries move slightly in the direction of the applied field. In a high torque stepper motor, magnetostriction deforms the iron, pulling the teeth of the rotor and stator in the air gap closer together, creating a noise.
Stepper motors produce a very low-pitched hum as a result of magnetostriction. The worst-case scenario for magnetostriction is low-speed stepper motors. Because of the often modest running speeds of motors used in laser printers and copiers, magnetostriction has the most detrimental noise effects on these devices.
While it is impossible to eradicate magnetostriction-induced noise, some metals are more susceptible to this phenomenon than others. When it comes to optimizing performance for certain applications, some materials strike a balance between magnetostriction and core losses.
All the moving parts and pieces that make up a stepper motor contribute to its mechanical noise. Mounting structures that are not securely fastened, shafts that are bent, and bearings that are either loose or nonexistent are common causes of noise. In each of these cases, resonant frequencies and undesired vibrations manifest. The motor housing, rotor balance, and bearing choice are further mechanical noise considerations.
Applications involving high-speed motors are greatly impacted by the structure of the motor housing. An unbalanced rotor will cause a frequency spike that is proportional to the motor's speed. Two kinds of bearings are commonly used in high torque stepper motors: rolling bearings and sliding sleeve bearings. Most people think that sleeve bearings are silent.
Because of the smooth surface of the bearing and shaft, a well-lubricated sleeve bearing will generate only extremely high noise frequencies. Rolling bearings are generally thought of as noisy, and numerous things could cause that to be true. Stiffening the mounting structures and selecting noise-dampening materials can significantly reduce mechanical noise. Some examples of this include encasing the motors in rubber or another sound-absorbing material, balancing the rotor, and utilizing well-maintained bearings.
There are several electrical noise generators for a stepper motor. Electrical noise, in contrast to mechanical and magnetic noise, can be facilitated by properly setting the stepper motor driver.
Microstepping and damping techniques are two of the various methods for making stepper motors quieter. Microstepping entails breaking each step into smaller increments to lessen the impact of vibrations and noise brought on by changes in the magnetic field. To further lessen the transmission of vibrations and noise, dampening solutions like rubber mounts or damping materials can be employed.
Keep in mind that the load being driven and operating conditions can also impact the noise level of high-torque stepper motors. You can increase the noise level by increasing the load and the speed and decrease it by decreasing both.
For over 30 years, Smooth Motor has been producing and selling high-quality stepper motors.
In addition to a wide selection of linear actuators and stepper motors, Smooth Motion Solution also provides a wide selection of mechanical components precisely matched to these components.
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