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 results for a 20 HP starter motor with a multiple clutch.
| Identifier | ExFiles\Box 56\4\ Scan113 | |
| Date | 23th November 1927 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} X5650 Hs{Lord Ernest Hives - Chair}/GWH{George W. Hancock - Head Chateauroux}12/LG23.11.27. X5300 20 HP. STARTER MOTOR TO LeC.2442. (MULTIPLE CLUTCH) We have now got this scheme to give very satis- factory results. There is no sign of thumping upon engaging. sufficient initial friction to rotate the unit and engage the pinion from rest, and wind up the buffer spring without slipping. The limited torque comes into action and allows the motor to spin when excessive load is applied such as a frozen motor or a gear inadvertently left in and brakes on. To obtain these results it is necessary to use cork washers, cushion spring of 12 lbs.,buffer or clutch spring of 130 lbs. at .650" deflection giving a slipping torque load of approx. 800 in.lbs. We found, after our last report, that we were being mislead in our results due to the buffer spring D.51378 being choc-a-bloc when the operating sleeve D.51582 came choc-a-bloc against the flange on shaft D.51576. To overcome this we reduced the thickness of the cork washers, and to obtain suffic- ient friction for the total torque load it was found necessary to bring the buffer or clutch spring load up to 130 lbs. at .650" deflection giving us a total torque load of 800 ins.lbs. We find that the torque load given in the LeC.2441 of 500 lbs.ins. allows too much slipping before the drive is taken up. In order to obtain definite figures of the unit we attached a 10" lever to the motor pinion and prevented the armature shaft from revolving. contd :- | ||