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).
Graph showing terminal volts at the motor using various batteries and starter cables.
| Identifier | ExFiles\Box 48\3\ Scan047 | |
| Date | 7th June 1921 | |
| TERMINAL VOLTS AT MOTOR OBTAINED WITH VARIOUS BATTERIES AND STARTER CABLES ON R-R CAR. TEMPERATURES 60°F to 80°F.{Mr Friese} EXPLANATION BATTERY VOLTAGE DROPS ARE APPROX. FROM TESTS THEY ARE VOLTAGES AFTER 5 SECS. DISCHARGE AT VARIOUS RATES. RESISTANCE OF MAIN SWITCH, TERMINALS &c. [OBSERVED] = APPROX. .20 VOLTS PER 100 AMPS RESISTANCE [VOLTAGE DROP] IN BATTERIES, ARE: WILLARD — 1 VOLT PER 100 AMPS. EXIDE L.X.R — 1.5 " " " " EXIDE XXC. — .8 " " " " DROP IN CABLES [CALCULATED FROM COPPER 9.75 ω PER O"MIL-FOOT] BIG TEST CABLE. 259 WIRES .0226 DIA. 148,000 O" MILS. -- 24 FEET = .16 V PER 100 A.{Mr Adams} STD. No. 0 CABLE. 133 WIRES .0285 DIA. 107,743 " " " " " = .22 V " " R.R. CABLE. 84 WIRES .0201 DIA 34,000 " " " " " = .69 V " " Graph Line Labels: S.R.L. STANDARD MOTOR TERMINAL VOLTS EXIDE 6XXC-13-1 [MAKER'S TEST] WILLARD SYRN 28 [OUR TEST] No. 0 CABLE AND 6XXC MOTOR TERMINAL VOLTS A.E.X. CABLE AND 6XXC MOTOR TERMINAL VOLTS No. 0 CABLE AND S.Y.R. MOTOR TERMINAL VOLTS EXIDE 6.L.X.R. 7-1 [MAKER'S AND OUR TESTS] STD. R.R CABLE 84-24 [34,000 O"MILS] AND L.X.R. MOTOR TERMINAL VOLTS. Axes Labels: VOLTS AMPERES Other text: KEUFFEL & ESSER CO., N.Y. No. 334 C 500 oy. JUNE 7 '21. X4W5 | ||