Item 50a. [Art.91.11] Slot Dimensions (Rotor)

Slot width (rotor), s_r
s_r = l_r /2
Should be a multiple of 1/8". For correction, when field winding dimensions are finalized. See item 62.

Slot depth (rotor), d_r-trial
d_r-trial = 1.5l_r
Should be a multiple of 1/8". For correction, when field winding dimensions are finalized. See item 62.

Slot wedge (rotor), d_wr
d_wr = 0.24d_r
The d_wr allowable working stress for manganese bronze or phosphor bronze wedges is about 14,000 lb per sq. in. See Article 158.

Item 50b. [Art.91.11] Tooth Dimensions (Rotor)

Tooth width (rotor) _top, t_r
t_r-top = F_NL / (S/p)_r x B"t x l_p)
Where: B"t is item 30, not exceeding 140,000 lines per sq. in.

Tooth width (rotor) _mid
t_r-mid = t_r-ave = [p ( D_r - d_r ) / S_r ] - s_r

Tooth width (rotor) _root
t_r-root = F_NL / (S/p)_r x B"t_max x l_p)
Where: B"t_max is (p/2) × item 30, not exceeding 140,000 lines per sq. in.

Tooth width (rotor) at Forge, t_f
t_f = p [ D_r - 2 x ( d_r + d_fr ) ] / S_r ] - f_r

Item 50c. [Art.91.11] Slot Forge Dimensions (Rotor)

Forge width (rotor), f_r
f_r = 0.5 s_r + 0.125

Forge depth (rotor), d_fr
d_fr = d_r/2 - 0.125

Item 51. [Art.91.12] Permeance per sq. cm of air gap (center), P
For each path, use P = (2/p) x ln[d + (ps_r/4) / d]
Total permeance, åP = P / l_r-ST x 2.54
Where P, is equal to the sum of the individual paths, P_x, computed with the following combinations:
Armature Slot to Rotor Slot
Armature Tooth to Rotor Tooth
Armature Slot to Rotor Tooth
Armature Tooth to Rotor Slot,
using: Px = (2 / p) x ln [ ( d + ps/4) / d]
Where the width s depends on the combination used.

Items 52 - 57

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