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 sheet for a switch with various operational features, dials, and safety mechanisms.
| Identifier | ExFiles\Box 164\3\ img217 | |
| Date | 1st May 1938 guessed | |
| Capacity. The Switch has single pole single throw silver contacts. It is rated at 10 amperes for 250 volts maximum and if required can also be supplied for lower commercial voltages on frequency controlled circuits. Housing. The Switch mechanism is enclosed in a moisture proof base and cover of moulded bakelite. The mechanism may also be supplied fitted in the base only. Day and Solar Dials. The Day and Solar Dials may be interchanged on site. The standard Day Dial is fitted with one "ON" and one "OFF" lever with which settings can be made for minimum periods of 20 minutes between "ON" and "OFF" operations. Extra levers up to three "ON" and three "OFF" with a similar minimum interval between settings can be supplied. Solar Dials are designed for different latitudes. Settings may be made up to three quarters of an hour on either side of normal sunrise and sunset times to compensate for longitudinal variation. Solar Dials are supplied with an extended midnight bridge with an "OFF" range from 8.30 p.m. to 1 a.m. They may also be fitted with an extra bridge providing a variable "ON" operation between solar times. Omitting Device. The Switch may be supplied with an Omitting Device to cut out the sequence of operations on any day or days of the week. This device must be specified when ordering as it is not a separate unit but a built in part of the Switch. The Switch can only be provided with one "ON" and one "OFF" lever when the Omitting Device is included. External Manual Operation. When required the Switch can be supplied with housing incorporating a push button by means of which the Switch may be operated externally by hand. Installation Features. The Switch will plug into standard street lighting post boxes, a feature of the bakelite base being that it also forms the plug receptacle and thus eliminates the need for a separate terminal block. A wiring diagram is moulded in the back of the base and the cover may be supplied either with or without a window. Provision is also made for external padlocking or sealing. Safety Factors. All live parts are situated behind the front plate of the Switch and are completely enclosed when the mechanism is fitted in the base. As an additional safeguard the base is also provided with an earthing terminal in connection with the mechanism. The Motor Circuit. The Switch is controlled by the Sangamo Type "G" self-starting synchronous motor, the circuit of which is fused on both sides. The fuses may be easily replaced and two spares are incorporated in the Switch. The watt loss of the motor is low. One Hour Dial. The Switch is also available fitted with a One Hour dial, the mechanism giving 1 revolution per hour to the centre spindle and dial. One "ON" and one "OFF" lever is provided but extra levers up to three "ON" and three "OFF" can be fitted. The switch may be set for minimum periods of 1 minute between "ON" and "OFF" and "OFF" and "ON" operations. BRITISH SANGAMO CO., LTD. — ENFIELD, MIDDX | ||