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).
Modifications to an improved Dynamo Battery Automatic Cutout.
| Identifier | ExFiles\Box 168a\3\ img240 | |
| Date | 25th October 1935 | |
| CAP Please note & return V.6999. WTT Hs{Lord Ernest Hives - Chair}/Wst. from E.{Mr Elliott - Chief Engineer} c. Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} Her. By.{R.W. Bailey - Chief Engineer} Mc. (Struck out) Ey/PD (Struck out) E.3/HP.25.10.35. Improved Dynamo Battery Automatic Cutout to RR. Sch.845. Referring to report Hs{Lord Ernest Hives - Chair}/Wst.10/MA.7.10.35, there seems to be very little wrong with this improved cutout, and it has accomplished the main purpose of the modification. With regard to the five points mentioned on page 3, we would comment as follows:- (1) The spring carrying the moving contacts was specified in 28 SWG (.0148). The spring cutout fitted for trial was 26 SWG (.018) which is nearly twice as stiff. This largely accounts for the effect experienced. From the filed down springs on the actual cutout we can obtain the correct gauge for the flexibility required, and this comes out at 30 SWG (.0124). (2) With the moving contact springs of the correct flexibility the deflection of the support carrying the fixed contacts is almost nil, but we can nevertheless have a small rib pressed into the back of this piece, which should greatly increase its rigidity. (3) There must be some mistake about this point because the single flexible fitted on RR. Sch.845 is exactly equivalent to the thinner double flexible fitted on the standard cutout. We propose to delete the flexibles in parallel with the armature and the core, and re-instate the present standard double flexible in parallel with the hinge. (4) The flexible connections to the shunt coil are exactly the same as standard, and it is possibly the increased handling of experimental testing that has caused these to fail. There is no complaint of this nature in service. | ||