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
Very quickly.
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.