Electric Motors & Transformers by Hand: Turns Ratios, Equivalent Circuits, Voltage Regulation, Efficiency, DC Motor Speed & Torque, Induction Motor Slip, Power Flow & Motor Energy Costs
See where the power goes inside transformers and motors. You will apply turns ratios, reduce a transformer to a simple equivalent circuit, compute voltage regulation and efficiency at every load, find the load of maximum efficiency, follow back-EMF, speed and torque in a DC motor, compute slip and the power flow of an induction motor, plot a torque–slip curve and compare the yearly energy cost of motor options, with every cell checked as you go.
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About this course
This course works through electric machines one spreadsheet cell at a time. You apply turns ratios and refer a load through an ideal transformer, reduce a transformer to one resistance and reactance, express it in per unit and compute voltage regulation with real and imaginary parts in separate columns. You split core and copper losses to find the efficiency at every load, the load of maximum efficiency and the all-day efficiency. You follow back-EMF, speed and torque in a DC motor and size a starting resistor, compute synchronous speed, slip and the power flow of an induction motor, plot a torque–slip curve and finish by comparing the yearly energy cost and payback of fan-motor options.
Lessons
- Ideal Transformers: Turns Ratio, Voltages, Currents, Apparent Power & Impedance Seen Through Pro
- Equivalent Circuit & Voltage Regulation: |Z|, Per-Unit Impedance and Phasors in Two Columns Pro
- Efficiency at Every Load: Fixed Core Loss, Copper Loss ∝ Load², Maximum Efficiency & All-Day Efficiency Pro
- DC Motors: Back-EMF, Speed and Torque, the Speed–Torque Line & a Starting Resistor Pro
- Induction Motors – Speed & Slip: Synchronous Speed, Slip, Rotor Frequency and Speed at Part Load Pro
- Induction Motors – Power Flow: Air-Gap Power, Rotor Copper Loss = s·P_ag, Shaft Torque & an Energy-Flow Chart Pro
- The Torque–Slip Curve: Starting, Maximum and Rated Torque, the Stable Region & the Operating Point Pro
- Capstone – Motor Energy Costs: Duty Cycles, Efficiency Classes, a Variable-Speed Fan & Payback Pro