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).
Production inspection and test specification for a 20/25 dynamo field resistance unit.
| Identifier | ExFiles\Box 163\6\ img270 | |
| Date | 23th February 1933 | |
| 23.2.33 SPECIFICATION OF PRODUCTION INSPECTION AND TEST OF 20/25 DYNAMO FIELD RESISTANCE UNIT. Type :- Two stage resistance for three-rate charge scheme. Active lengt s :- 15" and 48" (total 63") of 26 S.W.G. Eureka wire. ---------- A rig should be used with connecting pins on which a convenient number of resistances can easily be placed so that they are connected in series. These would be best placed in the position they would occupy on the distribution board i.e. with the recess in the edge face downwards, and at the base of the triangle. The 15" portion of the resistance will then lie along the side of the triangle to the observer's left and the 48" portion along the side to the right, the junction of the two being at the rivet at the top. (1) Inspection shall be made of the resistance coil turns that they are all spaced equidistantly and not making contact i.e. short-circuiting some of the turns. (2) The terminals of the arrangement should be connected through a switch, resistance and ammeter to a battery, so that the current flows through both portions of the resistance in series. With the current in the circuit adjusted to 1.0 ampere, voltmeter readings should be taken first between the left-hand terminal and the junction i.e. across the 15" resistance, and then between the left-hand and right-hand terminals i.e. across the whole resistance of 63". | ||