20.2 Generators and Motors
Generators and Motors
| GENERATORS AND MOTORS | ||
|---|---|---|
| Generators | • An AC generator results from rotating a coil in a magnetic field. • The rotating coil (ΔɸB) produces a current. • Mechanical work is converted to electrical energy. • The emf and current vary sinusoidally with time. | |
| ε = NBA ω sinωt N = # of turns B = magnetic field A = area of loop ω = angular speed = 2 π f |  | |
| Motors | • A motor is simply a generator run in reverse. • A current in the coil results in its rotation. • Electrical energy is converted to mechanical work. • The changing magnetic flux as the coil rotates results in a back emf which reduces the current in the coil. | |