From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Page of calculations to determine the best depth of a slot in an armature.
| Identifier | ExFiles\Box 68\4\ scan0230 | |
| Date | 1st January 1925 guessed | |
| X. 1640 BEST DEPTH OF SLOT IN ARMATURE Armature dia. = D Depth of slot = h No. of slots = n Total area = A Area per slot = a Width of slot = w Pitch at bottom of slot = p a = A/n, w = A/nh p = (π(D - 2h))/n Width of tooth at root = x = p - w = 1/n { π(D - 2h) - A/h } Total C.S. area of teeth at roots q = nlx = l { π(D - 2h) - A/h } dq/dh{D. Henderson - Showroom} = l { -2π + A/h² } = 0 for maximum q h² = A/2π or h = A/2π for best result. | ||