Hi friends, most probably you all have heard about servo motor and DC motor. Here in this article I will focus on the differences between servo motor & DC motor.
Functionality of DC Motor:
A DC motor is a 2 wire motor which is control by a switch. Here in DC motor when you switch ON power it`s shaft start rotating in a direction. As it is a 2 wire motor means all its drive power is supplied by these wiring. Normally you will get a constant speed DC motor in different devices like old tape recorder.
DC Motors are high speed (1000 rpm) motors. But you can change its speed by a gear assembly. You can also change its speed by using PWM (pulse width modulation) technique. Basically in PWM we reduce supplied power to DC motor. You can also change the direction of rotation by changing DC motor Polarity.
Functionality of Servo Motor:
Before understanding servo motor we should understand servo mechanism. Servo-mechanism is a continuous control mechanism which governs by a feedback loop. Here in servo motor feedback loop is a position sensor or for continuous rotation it may be an encoder circuit. Servo motor has three wires one is for drive voltage source, second wire is for Ground & third wire is for control signal.
Servo Motor has its own driving circuit which is integrated with its feedback sensor. Function of this driving circuit is to receive a signal (Shaft output position) and compare it with feedback signal of sensor and if there is an error, supply power to motor so that by achieving the position error will be zero. Servo motor have not a freely moving shaft, most of the motor have only 200-250 degree span. After some modification these motor can also be used in speed control application.
Difference between a Servo Motor and DC Motor
Here in given table you can easily understand the differences …
|Features||Servo Motor||DC Motor|
|Wiring & Terminals||The Servo motor has three wires known as power, ground and control.||DC motor has two wire known as power and ground|
|Assembly and System||Servo Motor is a system. It required a motor, feedback sensor & a control circuit||DC Motor is a individual device and can be operate by a power source.|
|Rotation||Servo motor does not rotate freely. Its rotation span is approximate 200 to 250 degree||DC Motor has 360 degree span.|
|Driver Circuit||Servo Motor requires a driver circuit||DC Motor doesn’t require driver Circuit|
|Cost||High cost with respect to DC Motor||Low Cost|
So finally at last servo motor is a combination of a DC Motor, Feedback sensor and a control circuit.
Here from YouTube I would like to show you a short video by which you can easily understand servo motor functionality and the difference between DC Motor & a Servo motor.