In Emetor, a winding is called fractional-slot winding when the number of slots per pole per phase is fractional and superior to 1.
In the Emetor winding calculator, fractional slot windings with a number of slots per pole per phase strictly superior to 1 are indicated with orange cells. In Emetor, only fractional slot windings with a number of layers equal to two are represented. Below is the example of the layout of a 2-pole 9-slot fractional slot winding which has a number of slots per pole per phase equal to 1.5:
Fig. 1 Double-layer 2-pole 9-slot fractional slot winding with a winding factor of 0.945.
Concentrated windings are also fractional slot windings, but they have a number of slots per pole per phase strictly inferior to 1.
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