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 and inspection procedure for a double value ballast resistance for an ignition coil.
| Identifier | ExFiles\Box 70\4\ scan0015 | |
| Date | 25th November 1927 | |
| 25.11.27. X.8781b. X.5781b. PRODUCTION TEST & INSPECTION OF BALLAST RESISTANCE (DOUBLE VALUE FOR IGNITION COIL). X.8720. X.5720. A rig should be used with connecting pins, on which three ballast resistances can easily be placed. The rig should contain a suitable switching arrangement to enable these resistances to be placed on first in series and then in parallel. (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 an ammeter to a 12 volt battery. Firstly, with the switch in the series position, voltmeter readings across each of the three ballast resistances should be taken in turn, and should lie between the limits 3.5 and 4.5. (3) Then the switch should be placed in the parallel position and the ballast resistances allowed to be warmed up for 8 minutes, during the last minute of which the current taken by the three in parallel shall fall within the limits 5.5 to 6.5 amperes. (4) Now reduce the voltage to 6, and after 5 minutes the current should fall between the limits 4.4 to 5.4 amperes. (5) Finally examine the connections of the ballast wire ends on the tags and ascertain by gentle trial that no weakness has been caused where the two working ends of the wire pass away from the joints. The porcelain also should | ||