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).
Letter from electrical insulation specialists H.D. Symons & Co. Ltd. discussing methods for high-pressure leakage tests on insulating papers.
| Identifier | ExFiles\Box 61\1\ scan0169 | |
| Date | 23th March 1931 | |
| [Letterhead] Telephone: KINGSTON 1708. Park Works, Kingston Hill, Surrey. Telegrams: INSULATION (PHONE) KINGSTON-ON-THAMES. [Logo 1: NATIONAL SCHEME FOR DISABLED MEN] [Logo 2: THE BRITISH ELECTRICAL AND ALLIED MANUFACTURERS ASSOCIATION (INCORPORATED IN THE YEAR 1905)] H.D. Symons & Co. Ltd. ELECTRICAL INSULATION SPECIALISTS. [Products listed in left margin] Varnished Cloth. Varnished Paper. Varnished Silk. Flexible Varnished Tubing. DUPLY TUPLEX Slot Insulation. EMLIN TAPE. FLEXIBLE MICA SILK. MICA PAPER. SYMOID CLOTH. Your Reference Our Reference HDS/AMP. 23rd March, 1931. [Stamp: RECEIVED 24 MAR 1931] Messrs Rolls Royce Limited, Nightingale Road, Derby. [Watermark: ROYAL BOND] Dear Sirs, H.T.-D.C. Tests of Insulating Papers or other Insulation. We thank you for your letter of the 11th instant with which you enclose general particulars of the arrangement of apparatus you employ for high pressure leakage test on insulating papers. As the writer explained when he had the pleasure of seeing your apparatus for conducting these tests, the idea of conductance tests for this sheet insulating material was new to us, and whilst we have no convenience for testing with such high voltage as you have arranged for your tests, we have convenience for carrying through conductance tests and we think it may be of value for us to outline the manner in which we have been testing the materials we have sent to you since the writer's visit to your Works. Our conductance tests have been made by means of a rectifier on an A.C. circuit giving us a continuous current of 300 volts, the leakage current being measured by a galvanometer. Only having 300 volts we have tested single layers of material. We understand that with your test of approximately 8,000 volts you test 15 layers which would give an average voltage per layer of about 500 volts. | ||