Electrical sem 1 - Unit 2 Magnetic Field Energy

How high of an efficiency can be achieved in electrical machines nowadays?

98%!!

What are sources of losses in an electro mechanical system?

• Copper losses

• Field Losses

• Mechanical Losses (friction)

• Aerodynamic / viscous losses.

What is Faraday’s law?

The law describes the relationship between voltage produced in a conductor and the rate of flux lines cut.

What do dWf, dWm and dWe stand for?

• dWe is change in electrical energy

• dWm is useful mechanical energy

• dWf is field energy

How is the field energy in an electromechanical system represented?

The area ABOVE the lambda against current curve.

How is the field co-energy represented on a lambda against current graph?

It is the area BELOW the curve.

What symbol is used to represent field co-energy?

What assumptions can be made for energy and co energy if the system is linear?

How is the force exerted a electro mangentic field calculated?

Taking the partial derivative of the field energy equation with respect to x (displacement).

How is it found if the system is linear?

• f is equal a half I squared time dL by dx

• f is equal to minus a half phy squared times dR by dx