Speed Control of DC Motor: Armature Resistance Control and Field Flux Control. Ward-Leonard system of speed control works on this principle of armature voltage control. FIGURE 5: Speed variation of a shunt DC motor due to armature control. The voltage of the generator is changed by changing the generator field current. (function() { Since they are connected in parallel, the armature … In armature-controlled DC motors, the applied voltage Va controls the angular velocity w of the shaft. A DC motor is a motor that converts direct current electrical power into mechanical power. This resistor RC is known as a Shunt Field Regulator. Variation of resistance in the armature circuit. Provided the motor excitation is kept constant, the DC drive power factor is proportional to motor speed. The detailed discussion of the various method of controlling the speed is given below. if (!IE) { return; } } In the latter case, the motor is said to be a permanent magnet DC motor and is driven by the armature coils only. Armature Voltage Control Method or Rheostatic Control The speed is directly proportional to the voltage applied across the armature. The introduction of variable resistance in the armature circuit or field circuit allowed speed control. As the supply voltage is normally constant, the voltage across the armature can be controlled by adding a variable resistance in series with the armature as shown in the Fig. })(); In this session we will discuss the armature voltage control technique of the speed control of dc shunt motors. Also See: Ward Leonard Method of Speed Control of DC motor or Armature Voltage Control. if (document.getElementById("af-form-1405154631")) { The armature voltage feedback method, also called armature feedback, relies on the ability of a DC motor to act as a DC generator. This example shows two DC motor control techniques for reducing the sensitivity of w to load variations (changes in the torque opposed by the motor load). But this method causes considerable power loss in the system. In this method, the magnetic flux due to the field windings is varied in order to … The speed of DC motor is directly proportional to armature voltage and inversely proportional to flux in field winding.In armature controlled DC motor the desired speed is obtained by varying the armature voltage.This speed control system is an electro-mechanical control system.We will discuss transfer function of armature controlled dc motor. Speed Control of D.C. Shunt Motor (Part3) 3. We can help! The speed of a DC motor can be controlled by changing the voltage applied to the armature. 3. Applied Voltage Control Multiple voltage control : In this technique the shunt field of the motor is permanently connected to a fixed voltage supply, while the armature is supplied with various voltages by means of suitable switch gear arrangements. One of the most important features of the dc motor is that their speed can easily be control according to the requirement by using simple methods. This speed control method is used only for small motors. The speed of a motor is proportional to the supply voltage. A separate variable voltage source is required in this method. This method involves high cost so it rarely used. The entire process is driven by applying electrical power to the coil, with the source voltage having a direct relationship to the motor’s output speed.