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 discussing design proposals and questions for alternating current motors.
| Identifier | Morton\M6\ img044 | |
| Date | 19th May 1928 | |
| REG. TELEGRAPHIC ADDRESS: "ROYCE, WEST WITTERINGHenry Royce's home town" } TWO WORDS ONLY. TELEPHONE: CHICHESTER 210. STATION- PASSENGER & GOODS: CHICHESTER-7 MILES. L. B. & S. C. RLY. "ELMSTEADHenry Royce's home in West Wittering," WEST WITTERINGHenry Royce's home town, NR. CHICHESTER. 19th. May 1928. Messrs Bentley & Coley. ROYCE LTD. MANCHESTER. Dear Messrs Bentley & Coley, ALTERNATING CURRENT MOTORS. Providing we can get a really good design of high speed motor (1500 revs.) and enclosed reduction gear, say 4 to 1, and such motors would meet buyers approval, (they would be more effic-ient) I propose we make a specimen of the most useful HP. I assume the following:- (1) The slip rings are inside between bearings. (2) The bearings shall be large deep groove ball for the main, and small roller bearings for the minor end, because of the extra strength and rigidity of the main bearing castings to resist end thrust if necessary. We should have to adopt some scheme of fixing the bearings so that they can be removed easily for taking out rotor. (I propose short quick taper and nut). This would mean better convenience for putting threads on shaft (thread milling?) 4 I understand there is practically one speed and one voltage, so that the variations from standard are less than C.C. 5 Might it be possible to make the end pull of the armature actuate the brake, but do we always put on the stator current when we remove the brake? 6 The taper armature could actuate multi-plate brake. 7 Do you lower the load by the rotor over-running the stator? 8 No slipper drive seems necessary for longitudinal with alternating current motors. 9 Should you need a slow lowering device with alternating current motors, you might have a tiny motor generator on board the crane, excite one phase of the stator with continuous current, and short the rotor more or less and thus make an electrical brake - possibly a patentable idea. 10 Motor generators of say 1500 revs. might be fitted up in cage, so that they could be stopped, and also voltage controlled at will. Here I am speaking of using C.C. motors for the crane, which gives you a crane which will do work in less time than an alternating current crane, and so might justify the extra cost. Yours faithfully, F.H. Royce | ||