Difference between Stepper Motor and DC Motor

DifferencesDigital ElectronicsElectronics & Electrical

An electric motor is an electromechanical energy conversion device which converts the electrical energy input into mechanical energy output in the form of rotation of shaft.

Based on the types of electric supply and working, the electric motors are classified in many types such as DC motors, induction motors, synchronous motors, stepper motors, servo motors, and many more.

In this article, we will highlight all the major differences between a stepper motor and a DC motor. But, before discussing the differences, let's start with some basics of stepper motor and DC motor.

What is a Stepper Motor?

A type of brushless DC electric motor for which a full rotation of the rotor is divided into equal steps is known as stepper motor.

The stepper motors consist of many evenly spaced windings of wire on its stator, these windings act as magnetic poles when electric power is supplied. The rotor of the stepper motor is made of permanent magnet pairs in a gear shape.

The stepper motor is equipped with an electronic motor controller that switches the current to each successive stator winding to magnetically move the rotor from one pole to the next.

As from the above discussion it is clear that the operator can control the rotation of the rotor effectively for precise and stepwise rotational movements, thus for this reason these motors are called as stepper motors.

One great advantage of the stepper motors is that they can provide a holding torque, i.e. a positive toque at zero speed, which makes these motor suitable for various positioning applications like robotics. However, the stepper motors are less efficient than normal DC motors.

The stepper motors are extensively used in hard disc drives, printers and many other control systems, etc.

What is a DC Motor?

As its name suggests, a DC motor is the type of electric motor that converts the electrical energy in form of direct current (DC) into mechanical energy (rotation of shaft).

The DC motors have two types of constructions namely brushed DC motor and brushless DC motor. But, when we use the keyword DC motor, it simply means that we are talking about brushed DC motor.

A DC motor consists of a stator part which forms the magnetic field system and a rotor part that acts as the armature of the motor. A commutator is also mounted on the shaft of the rotor. The commutator segments are connected to the ends of the armature winding. The carbon brushes are used to make the electrical contact with the commutator and the armature. Therefore, in order to start the DC motor, a direct current is allowed to pass into the armature winding through the commutator and brushes.

The electric current flowing through the armature winding produces a magnetic field which interacts with the magnetic field of stator to produce a torque on the rotor. Due to this torque, the rotor spins to produce output mechanical energy at the shaft.

The DC motors are commonly used in electronic devices, cranes, toys, elevators and lifts, power tools, and in many other appliances.

Difference between Stepper Motor and DC Motor

Though a stepper motor is also a DC motor, but there are many differences between them that are listed in the following table −

Basis of Difference Stepper Motor DC Motor
Definition A brushless DC motor in which a full rotation of shaft is divided into equal steps is called a stepper motor. A type of electric motor which uses DC power to produce mechanical energy is called a DC motor.
Type Stepper motor is a brushless motor. DC motor may be brushed or brushless motor.
Speed The speed of stepper motor is low, about 200 to 2000 RPM. DC motors have moderate speed range depending on the type of motor.
Torque-speed characteristics Stepper motors produce maximum torque at low speeds. The toque decreases as speed increases. DC motors produce high torque at low speeds.
Control mechanism The control mechanism of stepper motor needs microcontrollers. The control mechanism of DC motors is simple and no need of extra devices like microcontrollers.
Efficiency The efficiency of stepper motors is low. The DC motors have high efficiency around 85%.
Reliability The stepper motors are highly reliable. The reliability of DC motors is moderate.
Motion Stepper motors have incremental motion. DC motors have continuous motion.
Response Stepper motors give slow response. A DC motor equipped with feedback control can give a much faster response than a stepper motor.
Service type The stepper motors are not meant for continuous use because they tend to run hot when powered for a long duration. DC motors are designed to operate continuously without much problem.
Maintenance Stepper motors do not need constant maintenance because they do not have brushes. DC motors require constant brush maintenance to prevent failure.
Applications Stepper motors are used in various position control applications such as robotics, printers, hard disc drives, etc. DC motors are commonly used in toys, computers, cranes, kitchen appliances, lifts, etc.

Conclusion

The most significant difference that you should note here is that a stepper motor provides an incremental motion, while a DC motor provides a continuous motion. However, both stepper motor and DC motor are types of low-cost motors widely used in a number of applications.

raja
Updated on 22-Aug-2022 12:26:05

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