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).
Trial report on a standard test gap for magnetos and coil ignition systems.
| Identifier | ExFiles\Box 37\1\ scan 143 | |
| Date | 8th February 1923 | |
| X3199 EFC. PB.80. Feb 8th 1923. TRIAL OF STANDARD TEST GAP ON MAGNETOS AND COIL IGNITION. For the purposes of this gap, a third point spark gap was used, and adjusted so that regular sparking would occur consistently, as near as possible, at a peak voltage of 7,000, i.e. 5,000 R.M.S. volts on the transformer. The gap obtained after so adjusting was 2.4 mm. The chemical leak afterwards used in conjunction with the gap, was 5.5 microhmos. Tests were carried out with the standard gap on a Watford magneto, and Goshawk battery ignition, using the B coil on both eight and twelve volts. In the following results, the speed of the machine at which regular sparking occurs under the various conditions of the gap, is taken as the basis of comparison. For the magneto the lowest speeds are taken, and for the coil the highest are taken. Magneto Condition 1. Gap alone. 90 r.p.m. 2. Gap with leak across. 500 r.p.m. Coil (8 volts) Condigion 1. Gap alone. 1700 r.p.m. 2. Gap with leak across. 305 r.p.m. (12 Volts Condition 2. Gap with leak across. 895 r.p.m. Contd. | ||