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 procedure for a switch unit, specifying current limits and contact pressure.
| Identifier | ExFiles\Box 60\2\ Scan054 | |
| Date | 25th February 1932 guessed | |
| -3- contd. to the terminals of a six-volt battery, through an ammeter, and the current taken by the coils (with non-inductive resistance in parallel) at 6 volts at atmospheric temperature shall be noted. This shall lie within the limits 7.6 and 8.4 amperes. If it does not fall within these limits, there may possibly be an open circuit through the resistance coil and in that case a test should be made for continuity through the resistance coil alone. (3) With the switch unit standing flat on its base a gradually increasing current shall be passed through the coil of the main switch (with its non-inductive resistance in parallel) and the current noted at which the switch pulls right down operating also the auxiliary switch by means of the mechanical interlock. This current shall not exceed 7.0 amperes and should break reasonably sparklessly. (4) It should now be confirmed by means of a spring balance that this main switch is definitely capable of holding on contact with a copper contact pressure of 2.0 lbs. measured by hooking a spring balance to the lever side arm, when a current not exceeding 7.0 amperes, inclusive of the current passing through the parallel non-inductive resistance, is supplied to it, the auxiliary switch again being mechanically operated by the main switch lever sufficiently to completely break its top contacts and make its bottom contact. contd. | ||