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).
Specifications for the windings of an EAC Silent Starter unit.
| Identifier | ExFiles\Box 64\3\ scan0038 | |
| Date | 1st March 1924 | |
| X.8650. EFC3/T5. 3.24. X.8650. EAC. SILENT STARTER. In the second instance, the windings are as follows :- (1) For the actuator box solenoid unit, the wire is of the same size as the teazer winding on the motor field, i.e. 17 SWG. (.056") D.C.C. No. of turns 140. Length of mean turn 3.60". The calculated resistance of this winding at 45°C is .153 ohms. The amperes at 11 volts are 20.3 and the ampere turns therefore 2,840. The measured resistance of the second unit at 45°C is .154 ohms, amperes 20.3 and ampere-turns 2,840. (2) The main switch unit wire is 24 SWG. (.022") D.S.C. No. of turns 700. Length of mean turn 2.86". The calculated resistance of this winding at 45°C is 3.93 ohms. The amperes at 10½ volts are 2.67 and the ampere-turns 1,870. The measured resistance of the second unit at 45°C is 3.800 ohms, amperes 2.77, and ampere-turns 1,935. (3) For the hold-off coil unit, wire of 27 SWG (.0164") D.C.C. is used. No. of turns 300. Length of mean turn 2.86". The calculated resistance of this winding at 45° C is 3.03 ohms. The amperes at 11 volts are 3.63, and the ampere-turns 1,090. The measured resistance at 45°C of the second unit is 3.06 ohms., the amperes are 3.60 and the ampere-turns 1,080. EFC. | ||