STATE THE ENERGY BALANCE EQUATION AS APPLICABLE TO ALL SITUATION OF ELECTROMAGNETIC MACHINES. [7 marks]
Energy balance equation
A Machine accept energy in two forms either through mechanical or electrical from its terminal system. We take energy input to be positive. As the function of the mechanical energy conversion terminal input will normally be negative(-ve) of the total energy inputs, some converted, some stored and the rest dissipated in loss.
Therefore, (Elect Energy input) + (Mech Energy input)
= (Store field energy) + ( stored mech energy) + Dissipation
Comparable relations apply to energy changes and to energy rates (i.e power)
Energy changes: dwe + dwm = dwf + dws + de
Energy rate = Pe + Pm = dwf/dt + dws/dt + P
So energy rate equation becomes
Pe + Pm = P
