Here are two different types of motors, there is a stepper motor and a servo. Stepper and servo motors are famous types of motors for robots, automation and different manufacturing processes. These motors operate effectively and provide features advantages and disadvantages.. In this article, we will explore the basic principles of stepper and servo motors, discuss their components, and delve into their unique characteristics. So let’s get started with Servo vs Stepper motors
What is a Stepper Motor?
The stepper motor is a brushless dc motor that divides complete rotation in different steps or increments. The motor’s position is controlled without the use of a feedback system since motors move in discrete steps based on input pulses from the controller. Stepper motors are used where accurate speed control of rotation is needed and position like CNC machines, 3D printers, and robotics.
Stepper Motor Components
The stepper motor comes with different components that operate with each other through the conversion of electrical energy into mechanical.
The main components of this motor are rotors, stators, and motor windings.
The rotor is moveable component of a motor that comes with a shaft and permanent agents or soft magnetic material. The structure of the motor is based on stepper motor types.
permanent magent stepper motors come with a rotor or one or more permanent magnets that produce a magnetic field. For variable reluctance stepper motors rotor is made with soft magnetic materials having teeth like configuration that is configured to the teeth of the starter when filed is produced
The stator is the static part of the motor that comes with electromagnetic coils configured over the circumference of the motor. These coils called motor windings, are used for producing a magentic field that interacts with the rotor field. The interaction of the field resulted in rotor rotating in discrete steps.
What is a Servo Motor?
The Servo motor is part of a closed-loop control system that comes with a motor, control unit, and feedback system.
This motor comes with gearboxes for high-speed torque production. Servo motors are made for controlling the position, velocity, and acceleration of mechanical systems, and are best to use for different applications.
There is a need for high accuracy, responsiveness, and certain algorithms for the operation fo servo motors. These motors are used for CNC machines and automated manufacturing systems.
Types of Servo Motors
There are two main types of servo motors. The first one is AC servo motors and the second one is DC servo motors.
The AC servo motors are used for industrial uses since have high power putout, proper efficiency, and good speed.
DC servo motors are used in small battery-operated devices since have lower power needs and are easy to control
AC servo motors are further subtypes such as synchronous or asynchronous, that are defined based on rotor and stator magnetic fields.
Synchronous AC servo motors provide constant speed for different loads and roots rotate in a synchronized way to the stator’s magnetic field.
Asynchronous AC servo motors, also called induction motors rotates at a speed slower than the stator magnetic field. It helps motors to produce torque with the connection of rotor and stator magnetic fields.
DC servo motors further have two types brushed or brushless, based on the method of commutation for controlling motor current. Brushed DC servo motors use mechanical brushes for switching current in motor windings. Brushless DC servo motors use commutation, for high efficiency, reliability, and linger working life than brushed motors.
Stepper Motors vs. Servo Motors
| Feature | Stepper Motors | Servo Motors |
| Torque | low torque |
High-speed motor torque
|
|
Types of magnet
|
conventional magnets |
rare earth magnets like Neodymium and Alnico
|
|
Size and weight
|
Small and allow weight |
Large and heavy
|
| Speed | low to medium |
low to high
|
|
Operating system
|
open-loop system |
closed-loop system
|
|
Power consumption
|
Less power use |
High power consumption
|
| Pole count | (50-100) |
(4-12)
|
|
Position control
|
Low | More |
| Response | Fast | Slow |
Torque & Speed
These motors come with different speed and torque features that are defined based on factors that the motor has. For high-speed, stepper moors come with bad torque features. Servo motors produce speed between 2 and 4 times the speed of stepper motors.
Servo motors work for constant position feedback or closed loop systems, that oppose certain open loop systems of stepper motors.
That helps servo motors to operate at high speed and produces high peak torque. The use of rare earth agents for servos is more features that help ot produce in a small package.
System Control
The Stepper motor works on an open loop system which means constant current mode. A Stepper motor system working in constant current mode produces certain heat in motor and drive. that causes issues. It can be controlled by providing the motor current needed for holding the load.
Servo motors work with a closed loop system and a closed loop control system comes encodes for offering feedback. Feedback is data that is sent back from one point in the control system to another point. Servo motors are controlled by sending electrical pulses of variable width, called pulse width modulation.
Pole Count
Stepper motors use 50 to 100 poles while servor motors use four to 12 poles. The pole defines the area of motors where the north or south pole is produced through permanent magent or through passing current in windings. Every pole provides natural stepping for the motor shaft.
A high pole count of the stepper helps to produce holding torque and uses less power for zero speed. Steppers not needed encode as they can move between different poles and servo motors need an encoder to track position
Cost
Servo motors use rare earth agents and also have external features like encoders resulting in high cost. The physical size of the servo motor is larger than the stepper motors needed more materials for creation.
Stepper motors are less complicated. The Stepper control system is less cost and is best to use for low to medium acceleration, and high holding torque, and has flexibility for open or closed-loop operation.
Servo motors are high cost since are complex of the inner design. Stepper motor uses low-cost agents and incorporates gearboxes.
Faqs
What are the disadvantages of a servo motor?
- Servo motors needed safety circuits complicated controllers needed encoders and electronic support. peak torque is about 1% duty cycle.
What is the advantage of a servo motor?
- Servo motors are used for features to operate at high speed and maintain accuracy and efficiency. its high-speed operation is best used for packaging lines and assembly processes that need high-speed operation.
What is the difference between a servo and a stepper motor?
- Servo motors provide unparalleled accuracy, speed, and torque with the high cost and needed control system. While stepper motors are low cost and easy to control and not provide the same value of accuracy and high-speed performance
What are the applications of stepper motor?
- 3D printing equipment.
- Textile machines
- Small robotics.
- CNC milling machines.
- Printing presses.
- Gaming machines.
- Medical imaging machinery.
- Welding equipment.
Is servo motor AC or DC?
- Servo motorsare of two types ac servos and dc servos. The main difference is that two motors is the source of power. AC servo motors are based on electric outlets as compared to batteries such as DC servo motors.
What is the main function of the servo motor?
- The working of servo motors is to transform control signals of the controller in rotational angular displacement or angular velocity of the motor output shaft. A Servo motor drive the joints.
What is the working principle of a servo motor?
- AC servo motos use AC for working. They provide high torque to inertia ratios, making them best for high-speed acceleration and deceleration. The working of the motor controls the amplitude and frequency of the AC input signal to get precise motor control.
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