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 log documenting the results of speed and temperature tests on various moulding materials.
| Identifier | WestWitteringFiles\I\July1922\ Scan70 | |
| Date | 1st July 1922 | |
| Contd. -3- EFCL/T3.7.22. | Date of Test. | Moulding material. | Ref: | Carcass temp. reached previous to speed burst. | Test Speed. | Duration of test speed. | Result. | Further remarks. | |---------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------|------------------------------------------------|-------------|-------------------------|---------|-------------------------------------------------------------| | 23.6.22. | 1. Asbestos Elo. | a | 120 | 6250 | 2 mins. | Burst. | Only ferrule remained on shaft spindle. | | | 2. (N.B. It being understood that the figures given for the comm. which remained O.K. refer to a continuation of the test after the first comm. had burst, so that really the second comm. was subject to both these tests). | b | 100 | 6000 | 3 " | O.K. | | | 24.6.22. | 1. Asbestos Elo. | b | 100 | 6000 | 3 " | O.K. | | | | 2. Plain Elo. | c | 100 | 6000 | ¼ " | Burst. | Moulded core remained on spindle but was cracked longitudinally. | | 27.6.22. | 1. Asbestos Elo. | b | 93 | 6000 | ¼ " | O.K. | | | | 2. Mouldensite. | d | 93 | 6000 | ½ " | Failed. | 6 segments only flew out. | | 27.6.22. | 1. Asbestos Elo. | b | 83 | 6000 | ¾ " | O.K. | | | | 2. Mouldensite + | e | 83 | 6000 | 3 " | O.K. | | | 28.6.22. | 1. Ditto (continuation). | b | 100 | 5500 | 3 " | O.K. | | | | 2. | e | 100 | 5500 | ¼ " | Failed. | 6 segments flew out. | | 29.6.22 | 1. Asbestos Elo. | b | 105 | 6000 | ¼ " | O.K. | | | | 2. Bakelite. | f | 105 | 6000 | ½ " | Burst. | Only moulded core remained. Speed momentarily obtained 6420.| | 29.6.22 | 1 Mouldensite + | g | 100 | 6200 | 3 " | O.K. [arrow pointing down] | | | | 2. Plain Elo. | h | 100 | 6200 | 3 " | Burst | | | 29.6.22. | 1. Mouldensite. | g | 110 | 6100 | ½ " | Burst. | Moulded core remained on spindle | | | 2. Plain Elo. | h | 110 | 6100 | 3 " | O.K. | | | | | h | 107 | 6000 | 3 " | O.K. | | + In this case the commutator was baked for 24 hours at 140°C previous to being handed over for test. | ||