Speed Control of D.C. Shunt Motor (Part3) 3. Save my name, email, and website in this browser for the next time I comment. The armature voltage control of D.C. motor provides a) Constant torque drive b) Constant voltage drive c) Constant current drive d) None of the above The speed–current characteristic of a series motor is shown in the figure below. As with the shunt motor, resistance control is cheap but inefficient. This method involves high cost so it rarely used. In the armature control method, the speed of the DC motor is directly proportional to the back emf (Eb) and Eb = V- IaRa. Required fields are marked *. Armature Voltage Control of DC Motor. Armature Control for DC Motors. The motor field current I fm is kept constant so that the motor field flux ϕ m also remains constant. The motor back EMF (Eb) and Speed of … Additional advantages of armature controlled DC motors include: While armature controlled motors are fast and ideal for short, fixed processes, they have a few disadvantages to consider when comparing armature control vs. field control: When using the field control method for DC motors, the field is weakened to increase the speed or it can be strengthened to reduce the motor’s speed. To achieve this, either the stator voltage is kept constant or the stator coils are replaced by a permanent magnet. if (document.getElementById("af-header-1405154631")) { Voltage can be applied to the terminals of the DC motor or external resistance can be applied in the armature. The voltage of the generator is changed by changing the generator field current. As the shunt field is very small, the power loss in the shunt field is also small. A coil is placed in a magnetic field, and when an electric current passes through the coil, a torque is produced, causing the motor to turn. In this system, M is the main dc motor whose speed is to be controlled, and G is a separately excited dc generator. Flux Control Method. A DC motor is a motor that converts direct current electrical power into mechanical power. The armature resistance control method is used in applications that require speed variation for shorter periods of time, not continuously. Voltage Control of Speed Control of DC Series Motor In this method of speed control by inserting rheostat with the series field, we can control the armature voltage and thereby speed of the motor. This speed control method is used only for small motors. Unlike armature controlled motors, field control provides speeds that are above the normal range. } Question: Question 2 Given The Block Diagram (20 Marks) DC MOTOR ARMATURE CONTROL DC MOTOR SPEED CONTROL Open Loop Block Diagram Disturbance Input Td(s) Td(s) Input TLS) Output W(s) 2s+0.5 Transfer Function 1/(Js+b) Scope Va(s) Ta() Tm(s) 10 1/Ra Km Кь 0.1- 1.