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).
Specification for the running test of a 20/25 HP Dynamo.
| Identifier | ExFiles\Box 62\3\ scan0285 | |
| Date | 22th April 1932 | |
| SPECIFICATION OF RUNNING TEST OF 20/25 HP. DYNAMO. Armature :- 24 slot, 16 conductors. 18 S.W.G. Poles :- .015" air gap increasing to .055" Brush angles :- 13° 126° The machine is assumed to have all mechanical adjustments correct, and brushes approximately bedded. In connecting up for running, a field resistance unit should be connected in the field circuit, (between the positive and field terminals). Across the resistance unit should be connected a switch, so that the resistance which is normally short-circuited, can be readily inserted when required. (1) In order to get the brushes finally bedded and the commutator surface with its working skin formed, the machine should be run with end cover removed for 3½ hrs. at 2100 RPM., with a terminal voltage between 17.5 and 18.0. (2) At the end of the above run, the output of the machine should fall within the limits 14.5 and 15.0 amperes at 2100 R.P.M., with the voltage adjusted to 18.0 ± .1. If necessary the control brush should be adjusted to bring the output within these limits. (3) With the dynamo still hot it should show an open circuit voltage of 14.0 at not more than 1000 R.P.M. (4) With the dynamo still in the hot condition, the resistance should be switched into the field circuit, and the speed for the open circuit of 14.0 again taken. This should not be more than 1350 RPM. /Voltage (5) With the resistance short-circuited, now run the machine at varying speeds up to 4000 R.P.M., and observe that noise, brush sparking and mechanical balance are reasonable. Afterwards confirm the condition of the machine by a general inspection. (6) Apply an alternating voltage of 200 through a low c.p. lamp between terminals and case and confirm that no failure of the insulation occurs. Hs{Lord Ernest Hives - Chair}/Pgt. | ||