What are servo motors and their types

Servo motors are widely used for industrial purposes. Servo motors are small devices that have revolutionized the industrial domain by fulfilling the requirements of powerful and light weighted motor. Several motors have been invented to resolve various purposes, but the way servo motor has emerged is simply unmatchable. These are smaller and more powerful than any other motors.

The basic uses of servos are in radio controlled airplanes for positioning control surfaces such as elevators, rudders etc. They also prove to be an ideal choice for radio controlled puppets, cars and robots as well.

In fact, servo motors are extremely functional in robotics. They are small in size, have in-built control circuitry and are tremendously powerful in comparison to their size. The best thing about these small wonder machines is that it draws power in proportion to the mechanical load it bears. Therefore, a lightly loaded servo doesn't consume much energy.

In category of motors, servos are the special one as it is designed for applications that include velocity control, position control and torque control. These are called because of the following reasons:

1. Minimal electrical time constant.
2. Minimal mechanical time constant.
3. Permanent magnet of high flux density to generate the field.
4. Electro-mechanical brakes, which are fail-safe.

There are two basic types of servo motors used in modern servo systems – one AC Servo Motors and the other is DC Servo Motors.

AC servo motors: AC servo motors are based on induction motor designs. These are mainly two-phase, reversible, induction motors that are modified for servo operation. These small machines have the applications in areas where rapid and accurate response is required. In order to attain thee features these motors are designed with small diameter and high resistance rotors. Its high resistance helps provides nearly linear speed-torque feature for perfect and faster servo motor control. They can perform fast as their small diameter delivers low inertia for fast starts, stops and reversals.

DC Motors: DC motors on the other hand are based on DC motor designs. Their applications mainly include working as prime movers in computers, numerically controlled machinery and other applications where starts and stops are made rapidly and precisely. Being light in weight they have low-inertia armatures that take action swiftly in response to excitation-voltage changes. These servo motors usually involve printed-circuit, permanent-magnet and moving-coil or shell. The basic characteristics of DC Servo motor incorporate physical shape, inertia, shaft resonance, shaft configuration, costs, speed and weight.