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).
Specification for the insulation testing of Redmanol coil cases at various temperatures.
| Identifier | ExFiles\Box 70\4\ scan0022 | |
| Date | 8th June 1927 | |
| X8781cl EFC/T8.6.27. not issued. SPECIFICATION OF INSULATION TEST AT TEMPERATURE OF REDMANOL COIL CASES. With the six-volt RR. trembler coil No.6162 operating on a voltage of from 5.5 to 5.75 volts, and with the coil cases to be tested with the two electrodes in position (the inner electrode connected to the H.T. D.C. supply, and the outer to earth) placed in the oven. (A) With the supply switched on and the voltage measuring spark gap open so as to ensure that no sparks pass, and with no condenser connected external to the rectifying unit, the reading of the Weston galvanometer should be carefully noted, time being allowed to obtain a settled condition. (2) With the supply still on, the spark gap should be gradually closed until a breakover just occurs, when the supply may be switched off, the gap measured, and the equivalent voltage computed. (3) The ratio of the voltage so obtained to the reading of the galvanometer in microamperes should then, for an ambient temperature lying between the limits 15 to 25°C, not be less than that given in the following table :- At 15° 70 megohms. At 21° 53 megohms. " 16° 67 " " 22° 50 " " 17° 64 " " 23° 47 " " 18° 61 " " 24° 45 " " 19° 59 " " 25° 42 " " 20° 56 " (B) The additional condenser (external to the rectifying unit) of .3 mf. capacity shall now be connected up and the temperature in the oven raised to indicate 80°C by the thermometer, at which temperature it should be maintained for 20 minutes. At the end of this period leakage current and voltage observations should again be made ( as in (1) and the ratio of the volts to the micro-amperes should not be lower than 1.2 megohms. | ||