Complete Electrical Machines course for B.Tech EEE and GATE in 80+ video lectures: magnetic circuits, DC machines, single-phase and three-phase transformers, induction motors, alternators and synchronous motors. Watch in order: each lecture builds on the previous one. Modules: 1. Magnetic Circuits & Electromagnetic Induction (Lectures 1A-1R) 2. DC Machines: construction, windings, EMF equation, armature reaction, losses (2A-2J) 3. DC Motors: torque, characteristics, speed control (3A-3C) 4. Single-Phase Transformers: EMF equation, equivalent circuit, OC/SC tests, regulation, efficiency (4A-4H) 5. Three-Phase Transformers: winding connections, vector groups, Scott connection (5A-5D) 6. Three-Phase Induction Motors: rotating magnetic field, torque-slip, equivalent circuit, starting (6A-6K) 8. Alternators (Synchronous Generators): EMF equation, armature reaction, voltage regulation, two-reaction theory (8A-8J) 9. Synchronous Motors: starting, effect of excitation, synchronous condenser, applications (9A-9J) 10. Single-Phase Induction Motors: double revolving field, types, equivalent circuit (10A-10E) Solved problems for every module (Electrical Machines Tutorials): https://www.youtube.com/playlist?list=PL5TKV1tzb09kPh9xyaU8yZC4ph305bTty Notes & more: https://engineeringdevotion.com #ElectricalMachines #ElectricalEngineering #GATEEE
Curated by: Engineering Devotion (81 videos)
Speed Control Techniques for DC Motors: Armature Rheostatic & Field Flux Methods: Controlling the speed of DC motors is crucial for various applications. Two fundamental and widely used techniques are Armature Rheostatic Control and Field Flux Control. Armature Rheostatic Control involves inserting a variable resistance in series with the motor's armature circuit. This added resistance increases the voltage drop across it, thereby reducing the voltage supplied to the armature. As the armature voltage decreases, the motor's speed, which is directly proportional to the back EMF (and thus armature voltage), also decreases. This method is effective for achieving speeds below the motor's rated (base) speed. While simple and offering a wide range of speed control down to zero, its main drawback is significant power loss as heat in the external resistance, leading to reduced efficiency, especially at lower speeds. Field Flux Control, on the other hand, manipulates the magnetic field strength of the motor. In shunt motors, this is achieved by connecting a variable resistance (rheostat) in series with the shunt field winding. By increasing this resistance, the field current decreases, which in turn weakens the magnetic flux. Since motor speed is inversely proportional to the flux, weakening the field flux increases the motor's speed. This method is primarily used for obtaining speeds above the rated speed. It is generally more efficient than armature control because the field current is typically much smaller, resulting in lower I2R losses in the rheostat. However, excessive weakening of the field can lead to commutation problems and motor instability. Both methods offer distinct advantages and are chosen based on the desired speed range and application requirements. Important Search Queries: DC motor speed control methods Armature resistance control DC motor Field flux control DC motor shunt motor Speed control of DC series motor Advantages and disadvantages of armature control Advantages and disadvantages of field control DC motor speed control equation Rheostatic speed control of DC motor efficiency Flux weakening method DC motor Ward Leonard method DC motor #DCMotorControl #SpeedControl #ArmatureControl #FieldControl #ElectricalEngineering #MotorDrives #IndustrialAutomation #PowerElectronics #DCmotor #ElectricMotors --- Electrical Machines full course (lectures): https://www.youtube.com/playlist?list=PL5TKV1tzb09lbVthPhckKZ7JsnwHkWmFP Electrical Machines solved problems (tutorials): https://www.youtube.com/playlist?list=PL5TKV1tzb09kPh9xyaU8yZC4ph305bTty Notes & more: https://engineeringdevotion.com