Electrical Machines

Motors, generators and transformers — electromagnetism at work. How electrical and mechanical energy are converted. DC machines, transformers, induction and synchronous motors, generators and special-purpose machines — their construction, equations, characteristics, starting, control and selection.

• DC Machines — DC motors and generators convert energy using a commutator. Learn back-EMF, the torque and speed equations, shunt/series/compound characteristics, starting current, speed control and why brushed DC still matters.
• Transformers — Transformers change AC voltage and current with ~98–99 % efficiency using mutual induction. Learn the turns ratio, EMF equation, equivalent circuit, losses, efficiency, regulation, three-phase connections and testing.
• Induction Motors — The workhorse of industry: rugged, cheap three-phase motors that run by 'slipping' behind a rotating magnetic field. Learn synchronous speed, slip, the torque–slip curve, power flow, starting methods and VFD control.
• Synchronous Motors — Motors that lock exactly to the supply frequency. Learn the power-angle equation, excitation and V-curves, power-factor correction with over-excited machines, starting, hunting, and why permanent-magnet synchronous motors dominate EVs.
• Generators — Generators turn mechanical energy into electricity. Learn the alternator EMF equation, frequency–speed relationship, excitation and AVRs, governor droop and load sharing, and the conditions for synchronising to the grid.
• Special Machines — Steppers, BLDC, servo, switched-reluctance, universal and linear motors — the machines behind printers, drones, robots and appliances. Learn how each works, its control method and how to choose between them.