How will high specific loading according to rotating electric machine affect the efficiency?

High specific loading in rotating electric machines refers to the amount of electromagnetic load (i.e., the magnetic flux and current density) for a given size of the machine. This has several effects on efficiency:

1. Increased Losses: High specific loading typically results in higher electrical losses. This is because higher current densities lead to higher resistive or I^2R losses in the windings. Moreover, increased magnetic flux densities can lead to higher core losses due to hysteresis and eddy currents in the magnetic materials.

2. Temperature Rise: With increased losses, there is a corresponding increase in the temperature rise within the machine. High temperatures can reduce the efficiency of the machine due to the temperature dependence of the resistivity of the conductor material used in the windings. Higher resistivity at elevated temperatures means higher losses.

3. Material Saturation: Operating at high flux densities can push the magnetic materials closer to saturation. Once the material is saturated, any further increase in the current will not result in a proportional increase in magnetic flux, leading to a less efficient operation.

4. Cooling Challenges: High specific loading can necessitate more complex and energy-intensive cooling systems to manage the increased heat generation. The requirement for additional or more powerful cooling can reduce the net efficiency of the machine.

5. Potential for Improved Efficiency in Design: On the other hand, machines designed to operate at higher specific loadings can sometimes achieve higher overall efficiency despite the challenges mentioned. This is because