Test report on Lucas petrol pump switches detailing failures and recommendations.
| Identifier | ExFiles\Box 168a\2\ img383 | |
| Date | 19th July 1938 | |
| To By, from Rm {William Robotham - Chief Engineer} /HC. c. By {R.W. Bailey - Chief Engineer} /KD. 61351 Rm {William Robotham - Chief Engineer} /RC. {R. Childs} 10/WH.19.7.38. RE. LUCAS PETROL PUMP SWITCHES. In order that bought out electrical units should be kept up to R.R. standard, specifications have been issued and supplied to the makers. In order to keep a check on such units the Electrical Laboratory subject these to a periodic specified test. We have just completed such test on two Lucas petrol pump switches taken off production. We find that neither of these conform to the specification No.EL.6. The spring tension of the contacts should be within the limits of 2.75 lbs - 3.25 lbs; the tension of the two switches tested are as follows:- (1) Tension of positive contact 4 lb. 2 oz. Tension of "A" " 4 lb. 10 oz. Tension of "B" " 2 lb. 0 oz. (2) Tension of positive contact 2 lb. 7 oz. " " "A" " 0 lb. 10 oz. " " "B" " 1 lb. 4 oz. Switch (1) failed to pass specification on two counts, (a) spring tension too heavy resulting in deep grooves being formed in both the brass and insulation of the rotor, after 8000 operations. (b) the rotor had no definite location after the test, through the excessive contact pressure causing the corners of the rotor to be worn off. Switch (2) Spring tension too weak with a consequent large volt-drop at the end of the test. We recommend that all petrol pump switches in stock be examined with respect to contact pressure, and those outside the specification limits returned to the makers. Rm {William Robotham - Chief Engineer} /KCJ | ||
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).