Generators

• The structure of a simple generator is essentially the same as a motor. The difference is that now mechanical energy is converted into electrical energy.

Consider a coil of area A with N turns of wire rotating at a constant angular velocity w in a uniform magnetic flux density B. As the coil rotates, it cuts through the lines of flux. Another way to express this is to say that the flux linking the coil is changing.

At what point is the rate of flux-cutting greatest?

Rate of flux cutting = induced emf = BANwcos wtwith a maximum value, Eo = BANw when the coil is perpedicular to the field.

To increase the voltage induced you can increase B, A, N, w

W = 2 pi f

Powerstation generator

Inside the generator they move the magnet and have 3 coils equidistant inside the generator.

This leads the generator having 3 induced currents for 1 magnet.

See book – p 128

Flemming’s RIGHT hand Rule

Notice – induced current! Only use this in generators!