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).
Performance analysis of a C.A.V. Z.C. starter motor on a Goshawk engine.
| Identifier | ExFiles\Box 35\4\ scan 044 | |
| Date | 26th August 1921 | |
| X.4384 26.8.21. X.3247 - PERFORMANCE OF C.A.V. Z.C. STARTER MOTOR ON "GOSHAWK" ENGINE WITH 8.4 RATIO AND ESTIMATED FLUX ETC. X.4384. Motor torque, allowing 90% torque efficiency. 64.7 lb-inches. B.H.P. 1.28 Speed 1240 Engine speed 148 Amperes 195 Volts 8.85 Efficiency .55 Static torque 71.2 lb-inches (say) at 195 amperes. Φ = (T b x 10^8) / (1.41 x P Z C) = (71.2 x 2 x 10^8) / (1.41 x 4 x 84 x 195) = 154,000. Polar face 2.625 x 1.500 = 25.4 cm^2 B = 6070 Top tooth area = 3.33 x .225 x 2.7 x 6.45 = 13.06 cm^2 Btt = 11,790 lines per cm^2 Bbt = 17,700 " " E = (Φ Z N / (60 x 10^8)) x (P/b) = (154,000 x 84 x 1240 x 4) / (60 x 10^8 x 2) = 5.35 V = 8.85 V-E = 3.5 R = .0152 C = 230 amperes. EFC. | ||