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).
The specifications of an aero engine speedometer from The Record Electrical Co.
| Identifier | ExFiles\Box 165\4\ img079 | |
| Date | 12th June 1930 | |
| X1350. 12.6.30. X.1350. AERO ENGINE SPEEDOMETER MADE BY THE RECORD ELECTRICAL CO. Following a letter ref. HKN/LMG. of May 31st. from the Record Electrical Co. their representative Mr. Fuller visited us on 3.6.30 informing us that the speed indicator consisted of a D.C. generator with permanent magnet weighing about 8 lbs. and driven by means of a flexible. The generator feeds a cirscale instrument of diameter 8" with a fairly uniform scale, the moving element being a coil moving over a magnetic tongue. The scale is not perfectly uniform and it is necessary to calibrate each scale separately. At 3,000 R.P.M. as a generator the loading of the instrument is 10 milliamperes at 100 volts. A large proportion of the instrument resistance is electrically outside the coil and of manganin. The generator brushes are copper morganite with a large proportion of copper. Mr. Fuller left a general catalogue, and promised to send on a pamphlet dealing with the speed indicator apparatus. EFC. | ||