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).
Letter from F.H. Royce to Mr. J.C. Bentley with a design sketch for a small D.C. electro motor.
| Identifier | ExFiles\Box 180\M6\ img015 | |
| Date | 31th October 1929 | |
| Handwritten note at top: Not finally seen by Mr Royce. REG. TELEGRAPHIC ADDRESS: "ROYCE, WEST WITTERINGHenry Royce's home town." TWO WORDS ONLY. TELEPHONE: CHICHESTER 210. STATION — PASSENGER & GOODS: CHICHESTER—7 MILES. SOUTHERN RLY. Mr. J.{Mr Johnson W.M.} C. Bentley, ROYCE LTD. MANCHESTER. "ELMSTEADHenry Royce's home in West Wittering," WEST WITTERINGHenry Royce's home town, NR. CHICHESTER. 31st. October 1929. Annotations on drawing: LONG BOSSES FOR SET SCREWS SPIGOTS ON OUTSIDE < 3" > BELT OR GEAR MUST CLEAR FOOT DIA. MUST BE KEPT LARGE TO CLEAR FIELD COILS. HERE CONSIDERABLY REDUCED < 2.5" > < 4" > STEEL 1 1/4" DEEP POLAR EMBRACE ABOUT 124° Dear Mr. Bentley, For relatively high voltage- 200/460 V.{VIENNA} - a small D.C. electro motor should only be 2 poles, but even then a circular carcase seems best. It also leaves room for commutating poles if these are found desirable. The above design assumes a ring of wrought or cast steel deeper than usual -i.e. the length of armature core and field core only. The ring can be from tube or washers punched from scrap mild steel plate, say 1/4" thick, or a forged or cast solid ring, simple and rectangular in section without features. The feet, and all complications of shape are in the end covers of cast iron. The field coil is wound squarely and hydraulically pressed in to the curvature of the inside of the ring carcase - i.e. all the wires follow the same curvature. The field magnets include the poles, and are stamped from 1/16th. to 1/8" sheet steel. The Two pole end winding on armature takes extra end room assuming cylindrical ends. [strikethrough: followers] Yours faithfully, for F.H. Royce R.W. Harvey-Bailey | ||