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).
Data table showing variations with speed of a contact breaker.
| Identifier | ExFiles\Box 69\1\ scan0009 | |
| Date | 16th May 1924 guessed | |
| VARIATIONS WITH SPEED OF CONTACT BREAKER SPEED FRACTION: 3/8 THROTTLE ON VS{J. Vickers} SPEED = 700 r.p.m. η EFFICIENCY = x² / 2(y-x) TABLE DATA: Headers: z | n | S | r/S | Col_5 | Col_6 | Col_7 | Col_8 | x | y | C' | Sx | S/2y | AVERAGE D.C FRACTION | R.M.S A.C FRACTION | AVERAGE CURRENT (AMPERES) | R.M.S CURRENT (AMPERES) | FORM FACTOR | x²/2 | y/S - x | η Row 1: .2 | 14 | .0530 | 9.444 | T.077 | .7143 | - | - | 1.000 | 1.000 | 3.16 | .053 | .0265 | .456 | .649 | 1.442 | 2.05 | 1.42 | .500 | 8.44 | .059 Row 2: .4 | 28 | .1061 | 4.710 | T.043 | .9057 | .320 | - | .991 | 1.000 | 3.13 | .105 | .0530 | .395 | .585 | 1.249 | 1.85 | 1.48 | .490 | 3.719 | .076 Row 3: .6 | 42 | .1591 | 3.140 | T.362 | .638 | .0434 | .0019 | .957 | .998 | 3.02 | .152 | .0794 | .348 | .525 | 1.100 | 1.66 | 1.51 | .459 | 2.183 | .210 Row 4: .8 | 56 | .2122 | 2.354 | T.021 | .977 | .015 | .009 | .905 | .991 | 2.86 | .192 | .1051 | .308 | .470 | .974 | 1.485 | 1.525 | .410 | 1.449 | .283 Row 5: 1.0 | 70 | .2653 | 1.882 | .818 | T.152 | .152 | .023 | .848 | .977 | 2.68 | .225 | .1295 | .275 | .424 | .870 | 1.34 | 1.54 | .360 | 1.034 | .348 Row 6: 1.2 | 84 | .3183 | 1.570 | .682 | T.318 | .208 | .043 | .792 | .957 | 2.50 | .252 | .1520 | .248 | .384 | .784 | 1.215 | 1.55 | .314 | .778 | .404 Row 7: 1.4 | 98 | .3714 | 1.346 | .525 | T.415 | .260 | .068 | .740 | .932 | 2.34 | .275 | .1730 | .225 | .351 | .711 | 1.110 | 1.56 | .274 | .606 | .452 Row 8: 1.6 | 112 | .4244 | 1.180 | .512 | T.488 | .3076 | .094 | .692 | .906 | 2.18 | .294 | .1925 | .206 | .323 | .651 | 1.02 | 1.57 | .239 | .488 | .489 Row 9: 1.8 | 126 | .4775 | 1.047 | .455 | T.545 | .351 | .123 | .649 | .877 | 2.05 | .310 | .2094 | .190 | .298 | .601 | .943 | 1.57 | .211 | .398 | .530 Row 10: 2.0 | 140 | .5306 | .942 | .409 | T.591 | .390 | .152 | .610 | .848 | 1.93 | .324 | .2248 | .176 | .277 | .557 | .875 | 1.57 | .186 | .332 | .561 Row 11: 2.2 | 154 | .5836 | .858 | .373 | T.627 | .424 | .180 | .576 | .820 | 1.82 | .336 | .2390 | .161 | .259 | .518 | .818 | 1.58 | .166 | .282 | .589 Row 12: 2.4 | 168 | .6367 | .785 | .341 | T.659 | .456 | .208 | .544 | .792 | 1.72 | .346 | .2522 | .154 | .245 | .487 | .774 | 1.59 | .148 | .241 | .615 Row 13: 2.6 | 182 | .6897 | .726 | .315 | T.685 | .4842 | .235 | .516 | .765 | 1.63 | .356 | .2635 | .144 | .227 | .456 | .717 | 1.57 | .133 | .210 | .633 Row 14: 2.8 | 196 | .7428 | .673 | .292 | T.708 | .511 | .260 | .489 | .740 | 1.55 | .364 | .2745 | .136 | .215 | .430 | .681 | 1.58 | .120 | .184 | .651 | ||