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).
Responding to points raised regarding a small dynamo with a 36 slot armature.
| Identifier | ExFiles\Box 168a\3\ img104 | |
| Date | 8th July 1938 | |
| 6142 To Rm{William Robotham - Chief Engineer}/RC.{R. Childs} BY/RD.3/B.8.7.38. RE SMALL DYNAMO WITH 36 SLOT ARMATURE. In reply to the points raised in Rm{William Robotham - Chief Engineer}/RC.{R. Childs}5/MH.{M. Huckerby}6.7.38. (1) We have already issued a revised winding diagram to obtain an 8° brush angle. (2) Brush holder springs. These springs gave the correct brush pressure on the 1st. large dynamo, and low brush pressures are therefore, due to variation between springs. We have altered the detail of the spring to emphasise its operating values and obtain more uniform springs. (3) Since the thickness of the brush is .309 and not .300 as you state, we can obtain the clearance you now require by alteration to the brush alone. We are instructing a minimum clearance of .008 with a maximum clearance of .018. (4) Since the terminals can be assembled in 4 positions, this is merely a question of correct assembly. We would now like particulars of the performance of the small machine, i.e. cutting-in speed, commutation and maximum permissible output. BY/RD. | ||