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).
Test of C.C. type car heater NO.A.75 and Rheostat CT.776/2.
| Identifier | ExFiles\Box 137\2\ scan0019 | |
| Date | 7th February 1938 | |
| 12-7 EWS/JF MEMORANDUM 7th February, 1938. Report dated 4. 2. 38. From RESEARCH DEPT. To L.667. REPORT ON TEST OF C.C. TYPE CAR HEATER NO.A.75 AND RHEOSTAT CT.776/2 AS RETURNED FROM ROLLS ROYCE LTD., MOTOR NO. KLAXON ECM.11191 - 12 VOLT. Voltage across Circuit. | Volts across Motors | Volts across Rheostat | Current in circuit. Amps. | Motor Watts. | Rheostat Watts. | R.P.M. | Remarks. | Stud No. Motor tested without any preliminary running prior to test. 12.0 | RESISTANCE 7.9 OHMS | 3.7 | 8.3 | 1.05 | 3.88 | 8.7 | - | Motor not running. | 1 " | 6.34 | 4.46 | 7.54 | 1.19 | 5.3 | 8.96 | - | " | 2 " | 4.95 | 5.12 | 6.88 | 1.39 | 7.12 | 9.56 | - | " | 3 " | 3.55 | 6.22 | 5.78 | 1.63 | 10.15 | 9.44 | - | Just on point of turning | 4 " | 2.01 | 8.55 to 8.63 | 3.41 | 1.7 | 14.6 | 5.8 | 725 - 790 | Speed varies | 5 Above Motor removed from heater and Motor No.11213 substituted. Following readings are for cold condition. Motor No.11191 was found to speed up when pressure was applied to the end of the spindle. pressure. PRESSURE -> Volts across circuit | Resistance of Rheostat OHMS | Volts across Motor. | Volts across Rheostat | Current in circuit. | Motor Watts. | Rheostat Watts. | R.P.M. | Remarks. | Stud No. 12.0 | 7.94 | 3.78 | 8.22 | 1.035 | 3.92 | 8.51 | - | Not running. | 1 " | 7.96 | 3.80 | 8.2 | 1.03 | 3.92 | 8.45 | - | " | 1 " | 6.35 | 4.4 | 7.6 | 1.195 | 5.25 | 9.1 | - | " | 2 " | 5.05 / 4.94 | (6.4 / )6.75 | 5.8 / 5.25 | (1.115 / (1.062 | 7.14 / 7.52 | 6.46 / 5.85 | 1260 | Commenced to run. | 3 | ||