A $150hp,500V,6$ poles, $450$ rpm $,$ dc shunt motor has the following data; armature diameter of $54$ cm $,$ length of armature core of $24\mathrm{.}5$ cm $,$ average flux density in the air$-$gap of $0,55T,$ number of ducts is $2,$ with each duct being $1$ cm in width, stacking factor is $0\mathrm{.}92.$ Calculate the number of armature slots and design a detail suitable for the armature winding. Also determine the dimensions of the slot. The flux density in the tooth at one third height from the root should not exceed $2\mathrm{.}1$T