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).
Leakage tests on coil cases made from special grades of Bakelite.
| Identifier | ExFiles\Box 61\1\ scan0108 | |
| Date | 28th April 1930 | |
| X6011 PD.50. 28.4.30. X.6011. X.3613 LEAKAGE TESTS ON COIL CASES MADE IN SPECIAL GRADES OF BAKELITE. Coil cases made of two special grades of bakelite powder have been submitted for test by the production department. Particulars of these two grades are as follows. One is termed Bakelite X.616B Stiff, and is the grade of bakelite X616B modified in respect of the relative amounts of wood powder and resin contained which renders the powder stiffer to work when being moulded. It is found that parts made from this powder are not liable to contract as parts made from other powders, including the standard Redmanol, do. The other, bakelite XM.1000, is said to withstand tracking caused by sparks or arcs better than other grades of powder. Parts made from this powder appear to require some amount of baking, as part of the process, to make them equal mechanically to standard. One case in each powder was made and tested, the results being given below together with representative figures for the standard Redmanol case. Ratio in megohms. Material. 20°C. 80°C. 100°C. Std. Redmanol. 118.7 12.3 7.3 Bakelite X616B. Stiff. 5,970 42.2 24.4 Bakelite XM.1000 Inf. 2,280 462 As previously stated, the XM.1000 case was baked considerably in the making which would account for its exceptionally high insulation value at the various temperatures. This case however, was found to have contracted excessively and generally had the appearance of having shrunk. | ||