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).
Page of test procedures for a relay switch unit, continued from a previous page.
| Identifier | ExFiles\Box 64\3\ scan0218 | |
| Date | 15th March 1926 guessed | |
| -5- Contd. (3) It shall be verified that with the switch arm in the "off" position, the combined rating and set of the main spring is such that a current through the fine wire coil lying between the limits ______ amperes and ______ amperes satisfactorily operates the switch. If the current just to operate falls outside either of these limits, then the main spring should be re-adjusted. (4) The adjustment of the main spring (combined rating and set) must at the same time satisfy the condition that with the switch arm in the "on" position with a current of ______ amperes through the fine winding, a load [struck through]mainspring[/struck through] of not less than 3.0 lbs. weight, measured at the core on a spring balance, is required to break the contact of the lower contacts. (5) Whilst still warm from test (4), an alternating voltage of 205 shall be applied, through a lamp, between the windings (both) and the switch arm for one minute without breakdown. (6) The final test of this relay switch unit is to consist of testing under approximate operating conditions as described in Section III. EFC. | ||