Question

Typed please. How do motors and generators work from a physics standpoint? What’s the basic difference? How does a transformer work?

Answer 1

Motor : A motor consists of a coil of wire which rotates in a magnetic field . Mainly motor takes electrical energy and converts that into mechanical energy. The coil carries the current and the coil lies in a steady magnetic field. The forces exerted on the current-carrying wires create a torque on the coil. This torque helps in producing mechanical energy.

F  =  i dL X B

Generator: Generator converts mechanical energy in to the electrical energy. Mechanical energy rotates the coil at uniform angular velocity ω in the magnetic field B, it will produce a sinusoidal emf(voltage) in the coil.Let θ be the angle between B and the normal to the coil, so the magnetic flux φ is NAB.cos θ. Faraday's law gives:

• emf = − dφ/dt = − (d/dt) (NBA cos θ)

  = NBA sin θ (dθ/dt) = NBAω sin ωt.

Transformer: They transform voltages from one value to another (The term voltage is used rather than emf, because transformers have internal resistance).The working principle of a transformer is Mutual induction.The alternating current through the winding produces the alternating flux that surrounds the winding. If another winding is brought nearer to this winding, some portion of this alternating flux will link with the second winding. As this flux is continually changing in its amplitude and direction, there must be a changing flux linkage in the second winding or coil which results in generation emf(voltage) across the secondary winding.