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)
Synchronous Motor: Effect of Changing Excitations on Constant Load A synchronous motor is an AC motor where the rotor's speed is precisely synchronized with the frequency of the stator's rotating magnetic field. Unlike induction motors, its speed remains constant regardless of the load, as long as it doesn't exceed its pull-out torque. Changing Excitations on Constant Load When a synchronous motor operates at a constant mechanical load, varying its DC field excitation (rotor current) significantly impacts its electrical characteristics, particularly the power factor and armature current. The motor adjusts its power factor to maintain constant real power input for the given constant mechanical load. This behavior is often visualized using V-curves. Under-excitation (Weak Field): If the field excitation is reduced below the normal (unity power factor) value, the motor operates at a lagging power factor. The armature current increases as the motor draws more reactive power from the supply to compensate for the weak internal excitation. Normal Excitation (Unity Power Factor): At a specific excitation level (normal excitation), the motor operates at unity power factor, drawing minimum armature current for a given load. The reactive power exchange with the supply is minimal. Over-excitation (Strong Field): When the field excitation is increased beyond the normal value, the motor operates at a leading power factor. The armature current again increases, but this time, the motor supplies reactive power to the system, acting like a synchronous condenser. This characteristic makes synchronous motors valuable for power factor correction in industrial plants. In all these scenarios, the motor's speed remains constant (synchronous speed) because the load is constant and the motor maintains synchronism with the supply frequency. The primary changes are in the armature current magnitude and its phase angle (power factor). Important Search Queries in this Topic: Synchronous motor power factor control, V curves of synchronous motor, synchronous motor excitation effects, over-excited synchronous motor, under-excited synchronous motor, synchronous condenser operation, how synchronous motor maintains constant speed with varying excitation, power factor improvement using synchronous motor. #SynchronousMotor #ExcitationControl #PowerFactorCorrection #ElectricalMachines #V_Curves --- 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