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 W.O. Bentley discussing the design of alternating current cranes and motors.
| Identifier | ExFiles\Box 180\M6\ img041 | |
| Date | 12th June 1928 | |
| REG. TELEGRAPHIC ADDRESS: "ROYCE, WEST WITTERINGHenry Royce's home town." TWO WORDS ONLY. TELEPHONE: CHICHESTER 210. STATION—PASSENGER & GOODS: CHICHESTER—7 MILES. SOUTHERN RLY. "ELMSTEADHenry Royce's home in West Wittering," WEST WITTERINGHenry Royce's home town, NR. CHICHESTER. 12th. June 1928. [Handwritten Note Start] Ackd @R10/ Copy for Mr. Higgins 21/9/28 [Handwritten Note End] W.O. Bentley. ROYCE LTD. MANCHESTER. Dear Mr. Bentley, ALTERNATING CURRENT CRANES AND MOTORS. I think if the 5 ton crane D.C. is 30 ft. per min. with motors of 400/500 revs., then with A.C. they should be about 50 ft. per min. with motors of 750 revs.(8 pole 50 cycle.) My own impression is that A.C. standard machines of our small size should be 1500 or 1000 revs. (4 or 6 poles), and I am seeking for a good and convenient 2 speed arrangement for your hoisting, thus, 3 trains for slow speed, and 2 for high speed. So far the mid-gears seem to be epicyclic. A.C. motors seem less costly than D.C. per HP. to make even with slip rings. I think we should make only this (slip ring) type, perhaps ventilated and enclosed. Would this not cover 95% of the probable orders? I very much like the whitemetal key, but I do not like the whitemetal head; it would fatigue and stretch one thinks. It seems good to hand wind by passing the wire through the nearly closed slot, but in our sizes not to attempt filling the slot with laminated magnetic materials. The spiral rotor or stator is I should think necessary. In the use of housing I suggested these could be thin in sheet steel for popular sizes, and it seems that one end could be as I shewed screwed, and take all end play - i.e. the main bearing and the minor could be of the simpler type. The lubrication and all else would permit of this. I am impressed that such a scheme would be really good and passably economical. Yours faithfully, F.H. Royce | ||