What is Servo Motor?

The servomotor (or servo motor) is a powerful electric motor, powered by servomechanism. If the engine as a controlled device associated with servomechanism is a DC motor, then it is commonly referred to as a DC servo motor. When AC runs a powered motor, it is known as the AC Servo Engine.

A servomotor is a linear actuator or rotary actuator that allows for effective regulation of linear or angular direction, acceleration and velocity. This consists of a motor connected to a location input sensor. This often includes a complex controller, typically a specialized board expressly built for use with servo motors.

Working Principle of Servo Motor

The servo consists of the motor (DC or AC), potentiometer, gear assembly, and a power circuit. First, we use the gear assembly to reduce the RPM and increase the engine torque. Suppose, at the initial location of the servo motor shaft, the direction of the potentiometer knob is such that no electrical signal is produced at the output port of the potentiometer. Now the electrical signal of the error detector amplifier is provided to another input terminal. Now the difference between these two signals, one coming from a potentiometer and the other coming from another source, will be processed in a feedback mechanism and output will be provided in terms of an error signal. This error signal serves as the engine input and the engine begins to spin. Now the motor shaft is attached to the potentiometer and when the motor rotates, the potentiometer produces a signal. If the angular orientation of the potentiometer varies, the current input signal shifts. For some time, the direction of the potentiometer enters a place where the performance of the potentiometer is the same as the external signal received. There should be no feedback signal from the amplifier to the engine input at this point, because there is no gap between the external signal added and the signal produced at the potentiometer, so in this case the engine starts spinning.

Applications of Servo Motors

• The servo motor is used in robotics to activate movements, giving the arm a precise angle.
• The Servo motor is used to power, push and stop conveyor belts that hold the commodity together with several phases. E.g., marking of goods, bottling and packaging.
• The servo motor is installed into the sensor to adjust the camera lens to enhance the subject concentration.
• In a robotic vehicle, the servo motor is used to control robotic wheels, produce a lot of torque to move, start and stop the vehicle and control its speed.
• The servo motor is used in a solar tracking system to correct the angle of the panel so that each solar panel stays to face the sun.
• The Servo motor is used in metal forming and cutting machines to provide specific motion control for milling machines.
• The Servo motor is used in Textiles to control spinning and weaving machines, knitting machines and looms.
• The Servo motor is used in automatic door openers to control the door in public places like supermarkets, hospitals and theatres.

Servo Motor Winding

The servo motor consists of two spinning stators and a rotor winding. The winding of the stator is connected to the stationary section of the motor commonly known as winding of the piston. The winding of the rotor is connected to the revolving portion of the motor and this winding is  commonly known as winding of the piston.

What is a Stepper Motor?

Stepper motors are DC motors that move in discrete steps. They have several coils that are grouped into classes named "phases." The motor must move one stage at a time by energizing each step-in series.

You may obtain very specific positioning and/or speed regulation with a machine-driven move. For this reason, stepper motors are the engine of choice for several precision motion control applications.

Stepper engines come in a range of sizes and types and electrical characteristics. This guide explains what you need to learn to choose the best engine for your work.

Stepper Motor Working Principle

How does the stepper engine work? The stepper motor rotor is a permanent magnet, which when the current flows through the stator winding, winds the stator to produce a vector magnetic field. The magnetic field forces the rotor to spin at an angle such that the combination of magnetic fields of the rotor and the position of the magnetic field of the stator are aligned. If the vector magnetic field of the stator is shifted by a degree, the rotor always rotates at a degree with the magnetic field. Any time the electrical pulse is applied, the engine rotates one degree further. The angular acceleration of the signal is proportional to the number of pulse inputs and the amplitude is proportional to the pulse frequency. Altering the winding control order, the engine would be inverted. It will then monitor the movement of the stepper motor by regulating the number of pulses, the duration and the electrical sequence of each period of winding of the engine.

What is Stepper Motor drive?

The stepper motor drive is a circuit used to power or operate a stepper motor. It's often referred to as a stepper motor driver. The stepper motor drive typically consists of a controller, a driver and a motor link.

The stepper drive is a conductor circuit that regulates how the stepper motor works. Stepper drives operate by sending current to the stepper engine through various phases of pulses. There are four types: wave drives (also known as one-phase-on drives), two-phase drives, one-two phase-on drives and microstepping drives.

Applications of Stepper Motors

• As the stepper motors are digitally controlled using an input pulse, they are suitable for use with computer-controlled systems.
• They are used in numeric control of machine tools.
• Used in tape drives, floppy disc drives, printers and electric watches.
• The stepper motor is also used in X-Y plotter and robotics.
• It has wide application in textile industries and integrated circuit fabrications.
• The other applications of the Stepper Motor are in spacecraft launched for scientific explorations of the planets etc.
• These motors also find a variety of commercial, medical and military applications and are used in the production of science fiction movies.
• Stepper motors of microwatts are used in the wristwatches.
• In the machine tool, the stepper motors with ratings of several tens of kilowatts are used.

Differences between Servo and Stepper Motor

• Torque: The stepper motor provides almost the same torque as the equivalent height of the servo motor unit. A servo motor provides an extra time-dependent peak torque value, a more robust speed curve and higher efficiency, but a correctly designed stepper motor will help you achieve greater cost savings over a servo. It is important to note, however, that the stepper motors operate at full torque while the advantage of the servo motor is the ability to control the torque of the application.

• Applications: Unless the program needs full stabilization of standstill, the stepper motor is the right option. Servo motors, however, pulsate back and forth to stand still. Servo's are the best choice for vertical applications in which the engine must be still loaded and for smooth operation, while applications such as vision system positioning are better suited for stepper motors.

• Micro-stepping: Micro-stepping is a means of providing half-steps to a motor that offers fewer steps than is desired. Micro-stepping is achieved by dividing the current between the two poles in the engine, thereby increasing the resolution. However, micro-stepping may harm the stepper motor as it will decrease the torque by up to 30%.

• Acceleration: Stepper engines are not as versatile with torque as the servo motors are. Stepper engines need far more traction capacity than, at any other moment, the torque specifications would be inside the nominal curve of the stepper engine. The peak torque of the servo motor will fall between the peak torque curve and the Root Mean Square torque of the total loop.

• Power: If it is a stepper motor or a servo engine, the more recently added results in more torque. In this regard, the advantage of the stepper motor is the amount of torque that can be generated at a safe voltage.