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 test specification for an Ignition Coil Ballast Resistance to LOP. DW.296 using 'Glowray' wire.
| Identifier | ExFiles\Box 164\5\ img349 | |
| Date | 20th May 1938 | |
| SPECIFICATION NO. ELC. 11/B. Production Test of Ignition Coil Ballast Resistance to LOP. DW.296 ("Glowray" Wire) A rig should be used on which are connecting pins, over which three ballast resistances may be placed. The rig should contain a suitable switching arrangement to enable these resistances to be connected either in series, or, in parallel. (1) Inspection shall be made of the resistance coil turns to ascertain that they are all spaced equidistantly and not making contact with each other. (2) The terminals of the arrangement shall be connected through an ammeter to a 12 volt battery with the switch in the series position; voltmeter readings, across each of the three ballast resistances, shall be taken in turn, and shall lie between the limits of 3.75 and 4.2 volts. The current shall lie between the limits of 1.45 and 1.60 amperes. (3) The switch shall then be placed in the parallel position, and the ballast resistances allowed to warm up for two minutes, during the last minute of which the current taken by the three in parallel shall fall within the limits of 12.35 to 13.45 amperes. (4) Finally examine the connections of the ballast wire ends and ascertain that no weakness has been caused where the wires pass away from the joints. The porcelain should be gently tapped to enable any possible cracks to assert themselves. Further, see that the terminal bushes are reasonably tight in the porcelain holder, and make a good electrical contact with the ends of the wire. Rm{William Robotham - Chief Engineer}/RC.{R. Childs} | ||