Stepper Motors
As the name stepper motors suggests, the movement of the rotor occurs in the form of different phases or discrete phases. It is also known as stepping motor. The number of pulses fed into the controller circuit control the angular rotation of the stepping motor. Each input pulse produces one step of angular momentum.
The drive is supposed to be an analog-to-digital converter. It has an inbuilt logic, which causes the solid-state switches in the required sequence.
Servo Motors
A servo motor is a self-contained electrical device, which makes parts of a machine rotate with high efficiency and great accuracy.
The output shaft of this motor can be moved to a particular angle, position and velocity which is not there in a regular motor. The servo motor uses a regular motor and combines it with a sensor for positional feedback.
How they are different from each other
Stepping Motors and Servo Motors are almost same usage for positioning but are entirely different systems, each with its pros and cons. Many are under the misconception that there are vast differences between servo motors and stepper motors. Here, we attempt to dispel the notion and provide a more realistic view.
Torque – A stepper motor has the same torque as a servo motor frame of a similar size. A servo motor provides an additional time-dependent peak torque rating, a more flexible speed curve, and higher performance, but a properly sized stepper motor can help you realize better cost savings than a servo.
However, it is important to note that stepper motors operate at full torque whereas the advantage of a servo motor is the ability to control the torque in an application.
Applications – If an application requires absolute standoff stability, a stepper motor is the better choice. The servo motor, however, pulsates back and forth at standstill. Servo motors are the better choice in vertical applications in which the motor must hold the load for stable and smooth operation, while applications such as positioning of the sighting system are better suited for stepper motors.
Terminology – ‘Servo’ is the term used for a motor applied to a closed loop system. A stepper motor can be adapted for a similar application with the same functionality as a servo but at a lower cost and slower speed.
Micro-stepping – Micro-stepping is a means of providing half-steps to a motor that provides fewer steps than desired. Micro-stepping is achieved by dividing the current between the two poles in the motor which increases the resolution. However, micro-stepping can have an adverse effect on a stepper motor as it can reduce torque by up to 30%.
Acceleration – Stepper motors are not as flexible with torque as servo motors. It require more power upon acceleration than at any other time so the torque requirements for a stepper must be within the nominal curve.
The peak torque for the servo should be within the peak torque curve and the root means the square torque of the overall cycle.
Size – Manufacturers of stepper servo motors generally offer comparable frame sizes, with the only difference in size being the length.
This length allows different levels of torque and inertia to be achieved with a similar size motor, providing more power without increasing motor size or cost. The result is a more cost-effective solution that requires less installation space.
Speed – Servo has good speed and is also used for applications in which the motor provides higher rpm than required. In such cases, a belt drive, for example, a stepper motor will be quite sufficient.
Power – Whether it is a stepper motor or a servo motor, more current applied results in more torque. The advantage of a stepper in this respect is the amount of torque it can generate at a safe voltage.
MISUMI India is a leading supplier of stepper motors and servo motors in India. They have an extensive range of these products. MISUMI provides these stepper and servo motors at the very lowest price with high-quality standards. Contact them at their customer care service at 0124-4688 800 for more information about these items.
