Co Energy and The Field Energy

The Field Energy

Based on the Principle of Conservation of energy:. Energy is neither created nor destroyed; it is merely changed in form.

1. Energy Balance

A Mechanism for Electromechanical energy Conversion based on Magnetic fields. a Two-terminal lossless magnetic energy storage system

The electric Terminal has two Terminal Variables: (voltage), (current).

The Mechanical Terminal has two Terminal variables: (force), (position)

The loss Mechanism is separate from the Energy-storage Mechanism.

– Electrical losses: ohmic losses.

– Mechanical losses: Friction, windage.

A simple force producing device with a single coil forming the electric Terminal, and a movable plunger serving as the Mechanical Terminal.

The magnetic stored energy serves as a conduit for the interaction between the electric and Mechanical Terminals, or electromechanical energy conversion.

Consider the Electromechanical systems whose Predominant Energy-storage Mechanism is in magnetic fields. For motor action, we can account for the energy transfer.

The ability to identify a lossless-energy-storage system is the essence of the energy method. This is done Mathematically as part of the modeling process.

dWelec=dmech+dfld

Here, E stands for the voltage that the fluctuating magnetic stored energy induces in the electric terminals. The external electric circuit powers the Coupling Magnetic field and subsequently the mechanical output terminals via this reaction voltage. The coupling field and its impact on the mechanical and electrical systems,. As well as its response, are involved in the Fundamental energy conversion process.

dWelec=deidt=dmech+dfld

The Co Energy

The magnetic stored energy is a state function, determined uniquely by the values of the independent state variables λ and x

Co energy

In this case, the force is directly a function of the current. Energy or co energy may chosen as the state function purely for practical reasons.

For a magnetically linear system, the energy and co energy (densities) are numerically equal:

W_fld+W’_fld=λi

The force acts to either increase co energy at constant current or decrease magnetic field stored energy at constant flux. The force acts to increase the inductance in a singly excited device by pulling on members, which lowers the resistance of the magnetic path connecting the winding.