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 results for a self-starter motor with a 24-slot armature.
| Identifier | ExFiles\Box 34\3\ Scan150 | |
| Date | 4th April 1918 | |
| X.2642B - BRAKE TEST OF R.R. SELF STARTER MOTOR. 4.4.18. (with 24 slot armature). (Weight of pan and portion of rope = 13.ozs (Zero reading of spring balance = 3 3/8 lbs. (Lever ratio 13.85" : 7.35" = 1 : .53 | Load in pan(lbs) | Spring bal. reading (lbs) | Speed R.P.M. | Amps. | Volts. | Nett spring bal. reading. | S. (lbs) | T (lbs) | T-S (Lbs) | Torque (lb-Inches) | B.H.P. | E.H.P. | Efficiency | |---|---|---|---|---|---|---|---|---|---|---|---|---| | 20 | 9 | 380 | 156 | 10.0 | 5 5/8 | 2.92 | 20.81 | 17.89 | 89.45 | .539 | 2.088 | .258 | | 18 | 9 3/8 | 460 | 141 | 10.10 | 5 7/8 | 3.11 | 18.81 | 15.70 | 78.50 | .572 | 1.907 | .300 | | 16 | 9 | 560 | 128 | 10.20 | 5 5/8 | 2.92 | 16.81 | 13.89 | 69.45 | .617 | 1.750 | .353 | | 14 | 8 5/8 | 670 | 117 | 10.325 | 4 7/8 | 2.58 | 14.81 | 12.23 | 61.15 | .650 | 1.620 | .401 | | 12 | 7 7/8 | 785 | 107 | 10.425 | 4 1/2 | 2.28 | 12.81 | 10.56 | 52.80 | .657 | 1.493 | .440 | | 10 | 7 3/8 | 920 | 96 | 10.550 | 3 7/8 | 1.92 | 10.81 | 8.89 | 44.45 | .648 | 1.356 | .4775 | | 8 | 6 5/8 | 1075 | 85 | 10.675 | 3 | 1.59 | 8.81 | 7.22 | 36.10 | .6155 | 1.217 | .505 | | 6 | 5 7/8 | 1275 | 74 | 10.825 | 2 1/2 | 1.19 | 6.81 | 5.62 | 28.10 | .569 | 1.078 | .530 | | 4 | 5 | 1570 | 62.5 | 11.0 | 1 5/8 | .80 | 4.81 | 4.01 | 20.05 | .499 | .922 | .542 | | 3 | 4 1/2 | 1760 | 56.5 | 11.1 | 1 | .53 | 3.81 | 3.28 | 16.40 | .458 | .8405 | .545 | | 2 | 4 | 1970 | 50.5 | 11.2 | 1/2 | .26 | 2.81 | 2.55 | 12.75 | .398 | .758 | .525 | | 1 | 3 3/4 | 2200 | 44 | 11.29 | 1/4 | .13 | 1.81 | 1.68 | 8.40 | .293 | .666 | .440 | | 0 | 3 3/8 | 2465 | 37.5 | 11.375 | 0 | 0 | .81 | .81 | 4.05 | .1585 | .572 | .277 | | ||