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).
Starter motor power tests, detailing production test specifications and results due to delays with the standard test rig.
| Identifier | WestWitteringFiles\T\2July1929-December1929\ Scan080 | |
| Date | 2nd October 1929 | |
| To. R.{Sir Henry Royce} from EFC. c. SG.{Arthur F. Sidgreaves - MD} c. EV.{Ivan Evernden - coachwork} E.{Mr Elliott - Chief Engineer} c. De. Wor.{Arthur Wormald - General Works Manager} ORIGINAL. EFC1/ADL2.10.29. X7625 X7655' S.S. STARTER SYSTEM. STARTER MOTOR POWER. The results reported in our EFC4/AD27.7.29 were those of ordinary brake tests with the brake wheel on the motor spindle. Owing to delay in the provision of the production test rig for S.S. starter motor testing in the electrical production department, it was necessary for us to production test the first 75 motors on our experimental crankcase test rig. The specification of production test issued by us includes a "Load test" at 150 amperes at 9.0 terminal volts. Thus we had opportunity to observe the brake efficiency of each production motor at one electrical load, inclusive of the effect of the 15 2/3 : 1 gear reduction to the crankshaft. The production test requires that when the motor is brake loaded (after speed reduction) up to 150 amperes with the terminal voltage adjusted to 9.0, the brake torque shall exceed 900 lb-inches and the motor speed shall exceed 810 r.p.m. These figures correspond to a minimum B.H.P. of .738 and a minimum overall efficiency of .408. The motor (T) for which brake test results and curves were given in our EFC4/AD27.7.29 as already referred to shows the following figures at 150 amperes. | ||