Choice of Specific loadings - Design of Induction Motors

Choice of Specific loadings

Specific Magnetic loading or Air gap flux density

Iron losses largely depend upon air gap flux density

Limitations :

Flux density in teeth < 1.8 Tesla

Flux density in core 1.3 – 1.5 Tesla

Advantages of Higher value of Bav

•             Size of the machine reduced

•             Cost of the machine decreases

•             Overload capacity increases

For 50 Hz machine, 0.35 – 0.6 Tesla. The suitable values of Bav can be selected from design data hand book.

Specific Electric loading

Total armature ampere conductor over the periphery

Advantages of Higher value of q

•         Reduced size

•           Reduced cost

Disadvantages of Higher value of q

•           Higher amount of copper

•             More copper losses

•             Increased temperature rise

•           Lower overload capacity

Normal range 10000 ac/m – 450000 ac/m. The suitable values of q can be selected from design data hand book.