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).
Specifications and testing procedures for a relay switch, including a table of gap limits.
| Identifier | ExFiles\Box 70\4\ scan0140 | |
| Date | 5th March 1925 guessed | |
| -3- Contd. SECTION II. RELAY SWITCH. (1) First check over the various gaps which should be in accordance with the following table :- Position. Gap on upper contact. Gap between pole core & armature. Gap on lower contact. Gap at carbon contacts. Off. 0 .060 +10 -8 .080+10 -10 .044 +10 -10 (Depression) Carbons in contact. .020+5 -5 .035+20 -10 .045+15 -20 0 On. .045+8 -3 .015+5 -3 0 .055+25 -25 N.B. The various limits on this table are arranged on the supposition that:- (1) The gap between the pole core and the armature, with the switch in the 'off' position. (2) The upper contact gap with the switch in the 'on' position. (3) The upper contact gap with the carbons just in contact. with their respective limits, are first fixed. (2) Verify by means of a spring balance that the pressure between the upper contacts in the 'off' position of the relay switch lies between the limits 28 and 32 ozs. (3) The fine wire coil shall be connected to the terminals of a six volt battery and the current taken at six volts at atmospheric temperature shall lie between 2.0 and 2.2 amperes. (4) It shall be verified that the spring tension is such that not more than 2.10 amperes through the g fine wire coil are necessary to operate the switch. | ||