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).
Continued analysis of a ballast resistance and primary winding, comparing electrical properties and planning future tests.
| Identifier | WestWitteringFiles\N\2October1925-December1925\ Scan112 | |
| Date | 3rd November 1925 | |
| Contd. -2- EFCL/T3.11.25. The resistance of the ballast resistance cold is 2.25 ohms, as against our .84, and in approx. normal running conditions is 2.75 ohms as against our 1.35. Cold resistance of the primary winding is .66 ohm. as against our 1.18. The inductance of that winding is slightly less than ours, thus there is a much bigger proportion of resistance to inductance in this apparatus than in ours. It is probable that the same coil is used for their 6-volt systems, but with a smaller ballast. This, however, would mean that the current taken by this system on 12 volts would be greater than necessary. We have not yet run the distributor and observed the current on the complete system (we shall run a 10,000 mile bench test of this), but we have run the coil with our own standard ballast and contact breaker and distributor, and as would be expected, the running current in these circumstances is a good deal more than with our own standard coil. Tests will be made in due course to see if any advantage, other than constructional, is apparent with the nearly closed magnetic circuit type of construction. WB.{Mr Brazier/Mr Bell}51 & WB.{Mr Brazier/Mr Bell}57. attached. EFC. | ||