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).
Brake test report for a self-starter motor with a 45 slot armature and specific field coil configuration.
| Identifier | ExFiles\Box 34\3\ Scan157 | |
| Date | 12th April 1918 | |
| X.2642B. X.2642B - BRAKE TEST OF R.R. SELF STARTER MOTOR (with 45 slot armature and field coils two in series and two in parallel). (Weight of pan and portion of rope = 13 ozs. (Zero reading of spring balance = 3½ lbs. (Lever ratio 13.85" : 7.35" = .53 | Load in pan(lbs) | Spring bal. reading(lbs) | Speed R.P.M. | Amps | Volts | Nett spring bal. reading (lbs). | S (lbs) | T (lbs) | T-S (lbs) | Torque lb-inches | B.H.P | E.H.P. | Efficiency | |---|---|---|---|---|---|---|---|---|---|---|---|---| | 25 | 12¼ | 800 | 210 | 9.025 | 8¾ | 4.64 | 25.81 | 21.17 | 105.85 | 1.344 | 2.535 | .530 | | 20 | 10¾ | 980 | 182 | 9.3 | 6¾ | 3.51 | 20.81 | 17.30 | 86.50 | 1.344 | 2.266 | .598 | | 18 | 10 | 1085 | 167 | 9.45 | 6½ | 3.44 | 18.81 | 15.37 | 76.85 | 1.324 | 2.112 | .627 | | 16 | 9 | 1190 | 155 | 9.60 | 5½ | 2.92 | 16.81 | 13.89 | 69.45 | 1.310 | 1.993 | .6575 | | 14 | 7¾ | 1300 | 144 | 9.75 | 4¼ | 2.32 | 14.81 | 12.49 | 62.45 | 1.288 | 1.880 | .685 | | 12 | 6¾ | 1415 | 133 | 9.9 | 3¼ | 1.66 | 12.81 | 11.15 | 55.75 | 1.252 | 1.763 | .710 | | 10 | 6 | 1555 | 122 | 10.05 | 2½ | 1.32 | 10.81 | 9.49 | 47.45 | 1.070 | 1.643 | .7125 | | 8 | 5¼ | 1725 | 110 | 10.225 | 1¾ | .99 | 8.81 | 7.82 | 39.10 | 1.070 | 1.507 | .710 | | 6 | 4¾ | 1940 | 95 | 10.4 | 1¼ | .73 | 6.81 | 6.08 | 30.40 | .935 | 1.324 | .7055 | | 4 | 4¼ | 2290 | 79 | 10.6 | 1 | .53 | 4.81 | 4.28 | 21.40 | .777 | 1.123 | .691 | | 2 | 4¼ | 2515 | 70.5 | 10.725 | ¾ | .40 | 3.81 | 3.41 | 17.05 | .6805 | 1.013 | .671 | | 2 | 4 | 2840 | 61.5 | 10.85 | ½ | .26 | 2.81 | 2.55 | 12.75 | .5735 | .895 | .641 | | 1 | 3¾ | 3230 | 52.5 | 10.975 | ¼ | .13 | 1.81 | 1.68 | 8.40 | .430 | .772 | .557 | | ||