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 performance, safety and recommended modifications for special high output 20/25 dynamos.
| Identifier | ExFiles\Box 62\3\ scan0278 | |
| Date | 24th February 1932 | |
| X60.05 By/RD. From Hs{Lord Ernest Hives - Chair}/Wst. c. to SPT/Mr. Brock. c. to MD/SWB. Hs{Lord Ernest Hives - Chair}/Wst.4/MA.24. 2. 32. SPECIAL HIGH OUTPUT 20/25 DYNAMOS. We have proved on test that a much better output can be obtained with the present standard 48 coil 20/25 dynamo set for a reasonably safe maximum temperature rise, than with a boosted up old std 56 coil machine with an unsafe maximum temperature rise. We recommend therefore that in cases where customers with 20/25 chassis fitted with a 56 coil dynamo require a specially higher output it would certainly be the safest works policy to modify their machine with a new 48 coil armature with trailed poles etc similar to the present standard machine. We found on test that Mrs. Cadbury's dynamo set by the production dept for higher output gave a dangerous temperature rise and is we consider unsafe for use on a chassis where no charge resistance is used for day running. With regard to the total electrical load on Mrs. Cadbury's car we have ascertained that this is 14 amperes so that 60 watt headlamps are almost certainly being used. We have handed to Mr. Brock a std 48 coil dynamo of our own which we have set to give a reasonably safe maximum output for the use of Mrs. Cadbury. Hs{Lord Ernest Hives - Chair}/Wst. | ||