In this article we will learn about the servo motor working. We will also learn about the dc servomotors and ac servomotors. We discuss in detail about servo motor working and type also their application.
Servo motor working
Servomotor is also called controls motors. These motors are used in feedback control system as output actuators. Unlike large industrial motors, they are not used for continuous energy conversion. The basic principle of operation of these motors is the same as that of other electromagnetic motors. However, their design, construction and mode of operation are different. Their power ratings vary from a fraction of a watt to a few hundred watts. They have low rotor inertia and their fore; they have a high speed of response. Servomotors are widely used in radars, computers, robots, machine tools, and tracking and guidance systems, process controllers etc. servomotors are being used presently.
It is the servo motor working and it classified in two parts
1. DC servomotors
DC servomotors are separately excited DC motors or permanent magnet DC motors. Figure shows a schematic diagram of a separately excited DC servomotor. The speed of dc servomotors is normally controlled by varying the armature voltage. The armature of DC servomotors has a large resistance so that the torque-speed characteristics are linear and have a large negative slope (torque reducing with increasing speed. it is DC servomotor working .
The power rating of DC servomotors can vary from few watts to several hundred watts. In general, most high power servo motor are DC servomotors.
2. AC Servomotors
Presently, most of the AC servomotors are of the two-phase squirrel cage induction type for low power applications. Recently, three-phase squirrel cage induction motors have been modified for application in high power servo systems. It is AC servo motor working.
3. Two-phase AC servomotors
In figure shows the diagram of a two phase servo motors. The stater has two distributed wingdings which are displaced from each other by 90 electrical degrees. The motor torque can be easily controlled by varying the magnitude of the AC voltage to the control phase (phase a) of the motor a shown in while the second phase called the references phase (phase m) is excited at a fixed voltage synchronous AC voltage (both the voltages must be drawn from the same source) the motor torque gets reversed by phase reversal of the control phase voltage. It is the two-phase-AC servo motor working.
In servomotors of rating below a few watt, low inertia construction can be achieved by using a drags cup rotor illustrated in fig. it is to be observed that the rotor core stationary.
Comparison of servomotors with conventional motors
For knowing more about servomotor working we know about servomotor advantage.
Servomotor has the following advantages over large industrial motors.
1. Servo motor produce high torques at all speeds including zero speed.
2. They accelerate and decelerate quickly
3. They have low rotor inertia; therefore their direction of rotation can be reversed
A servomotor can withstand higher temperature at lower speeds or zero speed. As it can dissipate heat quickly.
Hence it is the servo motor over all working and type if you will find incorrect above please comment below in comment box.
For knowing more about servo motor working you must watch this video.