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).
Page from The Electrical Review journal discussing machine voltage and listing new patents.
| Identifier | ExFiles\Box 38\1\ Scan031 | |
| Date | 4th October 1918 | |
| 338 THE ELECTRICAL REVIEW. [Vol. 83. No. 2,132. OCTOBER 4, 1918.] machine voltage with increasing load. By over-compensa- tion the voltage will rise with the load, and with under-com- pensation it will fall. The strength of the compensating winding can be made to compensate for the ir drop re- sulting in a flat compounded generator. If a generator of the type under consideration is coupled to a motor, such a motor-generator is capable of transforming from a variable voltage to a constant voltage. Fig. 4 shows the performance on test of a motor-generator, the motor voltage varying from 400 to 150, and the generator voltage being maintained constant at 82 volts. As will be seen from fig. 4 the generator voltage rises slightly with the load, showing that the machine is over-compounded. If the motor of a motor-generator of this type be thrown directly on the line a voltmeter connected to the generator shows that the voltage, due to sudden acceleration, exceeds the rated voltage. The amount of this overshooting of the voltage depends upon the relative values of the time con- stants of the two multiple exciting circuits. For example, assuming that the rate of increase of the exciting current is nearly the same in both circuits then the flux in the un- saturated circuit will appear at a later time than in the saturated circuit. Consequently the negative voltage will not develop fast enough, resulting in the phenomenon which may be called over-shooting of the voltage. It is possible, however, to speed up the rate at which the cross magnetising current increases by the insertion of resistance in this circuit. The complete diagram of connections is shown in fig. 5, in which the permanent resistance is designated as R.{Sir Henry Royce} Tests have demonstrated that if this resistance is properly chosen it is possible to entirely eliminate over-shooting of the volt- age. In this figure there have also been added commutating poles to ensure perfect commutation. The resistance R also serves another purpose, namely, to keep the regulation of the machine approximately the same when the generator is cold as when hot. Assuming that the generator was built in accordance with fig. 5, without any resistance in the cross circuit, it is obvious that when the generator is cold the current in both exciting circuits will be larger than when hot. The main flux will not be influ- enced by this increased excitation, since saturation exists. On the other hand, the increased exciting current of the cross circuit will cause an increase in the cross flux resulting in an increase of the cross voltage. Since this voltage is negative, it follows that when the machine is cold the line voltage will be too low. By inserting a resistance of zero temperature coefficient the variation of the cross excita- tion is limited, and tests show that if the resistance R is approximately .4 or more of the resistance of the cross exciting circuit, the change of excitation, due to heating, will be limited to such an extent that the variation of voltage is less than 5 per cent., corresponding to a tempera- ture range of 100 deg. C. This generator is in reality a combination of two indepen- dent generators, one boosting the other; the machine must, therefore, be somewhat larger in size and weight than a standard machine of the same speed and output. On the other hand, there are several other conditions which tend to make this machine more economical than the standard. When the speed increases all flux densities, and hence the stability increases. In a machine of standard make in which the shunt excitation is regulated in order to maintain con- stant voltage, the flux densities and hence the stability, de- creases with increasing speed. Therefore, a standard machine requires much larger gaps than this new machine and, furthermore, the armature reaction in the standard machine must be chosen with due consideration to the speed range. In order to give an approximate idea of the size and weight of this type of generator, as compared with the standard type, it may be stated that by a sacrifice in the efficiency of approximately 10 per cent., the new machine will have the same weight as a standard type of the same rating. This type of constant potential generator shows some distinct advantages over a standard generator with automatic voltage control. Where reliability of service is concerned this new type is claimed to be superior, since there are no automatic devices for maintaining the regulation. The new machine has also the advantage of being instantaneous in action, even at violent and large speed variations. Therefore, it is thought that this new machine will satisfy a long-felt need in certain applications of the electrical industry. 13,102. " Electric signalling telegraph." W. F.{Mr Friese} GEARTON. September 17th. 13,103. " Converting a.c. and c.th.d. into continuous power for gene- rating electric current." R.{Sir Henry Royce} A.{Mr Adams} FAYERS. September 17th. 13,104 " System of production of undamped electrical oscillations for wireless telegraphy." F.{Mr Friese} SERVENTAI. September 17th. 13,123. " Automatic or semi-automatic exchange systems." D.{John DeLooze - Company Secretary} A.{Mr Adams} LINTON. September 17th. 13,124. " Energy meters for alternating electric current." FORGES DES LORGRENES FRANCILLON & Co. September 17th. (Switzerland, September 17th, 1917.) 13,132. " Dynamo-electric machines and motors." W. ALBERD. Septem- ber 18th. 13,187. " Electromagnetic switches." BRITISH THOMSON-HOUSTON Co. & H.{Arthur M. Hanbury - Head Complaints} C. HASTINGS. September 18th. 13,188. " Electric heating devices." BRITISH THOMSON-HOUSTON Co. (General Electric Co., U.S.A.) September 18th. 13,197. " Sparking plugs for internal-combustion engines." Soc. CLOANET, BLIN ET CIE. September 18th. (France, September 18th, 1917.) 13,197? " Electromagnetic recording apparatus for telegraphic circuits." J.{Mr Johnson W.M.} E.{Mr Elliott - Chief Engineer} WRIGHTMANS (R.{Sir Henry Royce} C. Cox). September 18th. 13,214. " Electric power supply systems." C. R.{Sir Henry Royce} WOODLAND & R.{Sir Henry Royce} WOOD- LANDS. September 19th. 13,228. " Means for closing electric circuit for certain period." AKTIE- SELSKABET MEKANO & H.{Arthur M. Hanbury - Head Complaints} A.{Mr Adams} SCHEPMAN. September 19th. 13,230. " Means for making sealed joint between wall of vitreous mate- rial and electric conductor which passes there through. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} C. CHILTON AND OSRAM-ROBERTSON LAMP WORKS. September 19th. 13,233. " Electrical apparatus for transmitting motion step-by-step to re- ceiver." A.{Mr Adams} RABBA, BARR & STROUD AND W. STROUD. September 19th. 13,243. " Electrical boring machine." P. ELINGAARD & E.{Mr Elliott - Chief Engineer} SORENSEN. September 19th. 13,277. " Electric accumulators or secondary batteries." E.{Mr Elliott - Chief Engineer} J.{Mr Johnson W.M.} CLARK AND HART ACCUMULATOR Co. September 20th. 13,289. " Control gear for electric motors." J.{Mr Johnson W.M.} LEWIS. September 20th. 13,299. " Magnetic devices for detection of submerged objects or firing of mines." H.{Arthur M. Hanbury - Head Complaints} GERRARD & G.{Mr Griffiths - Chief Accountant / Mr Gnapp} F.{Mr Friese} PAXTONS. September 20th. 13,300? " Detection of conducting bodies submerged in electrolyte." A.{Mr Adams} G.{Mr Griffiths - Chief Accountant / Mr Gnapp} HARDING. September 20th. 13,302. " Electric furnaces." P. W. FAWCETT & J.{Mr Johnson W.M.} R.{Sir Henry Royce} HOYLE. Septem- ber 20th. 13,306. " Device for detachably connecting electric conductors to termi- nals of magnetos." A.{Mr Adams} G.{Mr Griffiths - Chief Accountant / Mr Gnapp} HARDING & G.{Mr Griffiths - Chief Accountant / Mr Gnapp} F.{Mr Friese} JOSEPH. September 20th. 13,320. " Electric furnaces." BRITISH THOMSON-HOUSTON Co. (General Electric Co., U.S.A.) & H.{Arthur M. Hanbury - Head Complaints} GERRARD. September 20th. 13,345. " Electric blast-furnaces." J.{Mr Johnson W.M.} BIBBY & J.{Mr Johnson W.M.} O.{Mr Oldham} BOVING. September 20th. 13,346. " Telephone transmitters." WESTERN ELECTRIC Co. (Western Elec- tric Co., U.S.A.) September 20th. 13,353. " Holders for incandescent electric lamps." J.{Mr Johnson W.M.} B. BELCHER. Sep- tember 21st. 13,367. " Electrically-heated warming or cooking plates of the enclosed type." F.{Mr Friese} P. FLETCHER. September 21st. 13,375. " Telephone switching apparatus." AUTOMATIC TELEPHONE MANU- FACTURING Co. & SAVIN & R.{Sir Henry Royce} W. WOOD. September 21st. 13,402. " Electrical apparatus." A.{Mr Adams} M.{Mr Moon / Mr Moore} Low. September 21st. PUBLISHED SPECIFICATIONS. The numbers in parentheses are those under which the specifications will be printed and abridged, and all subsequent proceedings will be taken. 1917. 4,118. ELECTRIC WELDING MACHINES. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} Gandolfo. March 21st, 1917. (118,422.) 5,617. IGNITION MAGNETOS FOR INTERNAL-COMBUSTION ENGINES. J.{Mr Johnson W.M.} E.{Mr Elliott - Chief Engineer} Mail- vert. April 28th, 1916. (106,482.) 9,489. ELECTRICALLY-HEATED COOKING STOVES. C. W. Winterbotham. June 30th, 1917. (118,423.) 9,889. TREATMENT OF MAGNETIC MATERIAL SUITABLE FOR USE IN STATIC TRANS- FORMERS AND OTHER ELECTRIC APPARATUS. A.{Mr Adams} F.{Mr Friese} Berry. June 30th, 1917. (118,423.) 11,890. IGNITION MAGNETOS. R.{Sir Henry Royce} J.{Mr Johnson W.M.} Foster. August 17th, 1917. (118,432.) 12,131. SYSTEM FOR THE PROTECTION OF THREE-PHASE ALTERNATING CURRENT CIRCUITS. R.{Sir Henry Royce} J.{Mr Johnson W.M.} Jensen. August 24th, 1917. (118,437.) 12,383. ELECTRIC MOTORS WITH COMPRESSORS OR PUMPS. W. J.{Mr Johnson W.M.} Sturges. August 27th, 1917. (118,443.) 12,427. IGNITION DEVICES. E.{Mr Elliott - Chief Engineer} C. R.{Sir Henry Royce} Marks (Splitdorf Electrical Co., U.S.A.). August 29th, 1917. (118,449.) 12,430. ELECTRICAL SWITCHES. H.{Arthur M. Hanbury - Head Complaints} W. Cox. August 30th, 1917. (118,450.) 12,501. ELECTRICAL ACCUMULATORS. C. H.{Arthur M. Hanbury - Head Complaints} Worsnop. September 1st, 1917. (118,454.) 13,393. AUTOMATIC TELEPHONE CENTRAL-STATION APPARATUS. A.{Mr Adams} E.{Mr Elliott - Chief Engineer} Stevens. September 14th, 1917. (118,478.) 13,394. ELECTROMEDICAL COILS. M.{Mr Moon / Mr Moore} H.{Arthur M. Hanbury - Head Complaints} Goldstone. October 6th, 1917. (118,479.) 16,251. RAILWAY SIGNALLING. McKenzie, Holland & Westinghouse Power Signal Co. (Union Switch & Signal Co., U.S.A.). November 7th, 1917. (118,514.) 16,839. STARTERS FOR INTERNAL-COMBUSTION ENGINES. A.{Mr Adams} H.{Arthur M. Hanbury - Head Complaints} Midgley and C. A.{Mr Adams} Vandervell & Co. November 16th, 1917. (118,519.) 16,931. CARBON BRUSHES AND BRUSH-HOLDERS OF ELECTRIC MOTORS AND GENERATORS. Veritys, Ld., & C. R.{Sir Henry Royce} Allen. November 17th, 1917. (118,520.) 17,991. INDUCTION COILS. M.{Mr Moon / Mr Moore} A.{Mr Adams} Codd. November 29th, 1917. (118,524.) 18,559. ELECTRIC CURRENT CONTROLLERS. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} Ellison & J.{Mr Johnson W.M.} Anderson. De- cember 10th, 1917. (118,536.) 1918. 861. ELECTRIC FANS. British Thomson-Houston Co. (General Electric Co., U.S.A.). January 15th, 1918. (118,546.) 4,014. CIRCUIT BREAKERS FOR IGNITION MAGNETOS. Gibbons & Extress. Sep- tember 5th, 1917. (118,582.) 4,334. HIGH-TENSION ELECTRIC FUSES. A.{Mr Adams} Nelson. April 12th, 1917. (114,831.) 4,374. DISC OR SHAPED STRAIN INSULATORS AND THE LIKE. H.{Arthur M. Hanbury - Head Complaints} O.{Mr Oldham} Busch-Jensen. March 12th, 1918. (118,584.) 7,722. PROTECTIVE DEVICES FOR ELECTRIC CIRCUITS. British Thomson-Hous- ton Co. (General Electric Co., U.S.A.). May 8th, 1918. (118,595.) 8,978. ELECTRICAL FUSE CARRIERS. A.{Mr Adams} C. Robinson & A.{Mr Adams} C. Cocketts. May 6th, 1918. (118,604.) 9,751. CONTROL OF ELECTRIC MOTORS. British Westinghouse Electric and Manufacturing Co. June 13th, 1917. (116,959.) 9,976. ELECTRICAL CONDENSERS. Philips-Brutton Co. July 29th, 1917. (118,640.) 11,478. TIMING MECHANISM FOR IGNITION SYSTEMS. Bosch Magneto Co. September 20th, 1917. (119,087.) NEW PATENTS APPLIED FOR, 1918. (NOT YET PUBLISHED.) Compiled expressly for this journal by Messrs. Sefton-Jones, O'Dell and Stephens (successors to W. P. Thompson & Co., of London), Chartered Patent Agents, 285, High Holborn, London, W.C. 1. 13,069. " Electric igniting devices." E.{Mr Elliott - Chief Engineer} G.{Mr Griffiths - Chief Accountant / Mr Gnapp} PULFORD. September 16th. 13,048? " Temperature indicators for transformers, &c." BRITISH THOMSON-HOUSTON Co. (General Electric Co., U.S.A.). September 16th. 13,049. " Electric switches." R.{Sir Henry Royce} K.{Mr Kilner} DAMEY. September 16th. 13,052. " Ignition magnetos for internal-combustion engines." M.{Mr Moon / Mr Moore}-L. MAGNETO SYNDICATE & E.{Mr Elliott - Chief Engineer} A.{Mr Adams} WATSON. September 16th. 13,055. " Alternating-current switches." W. J.{Mr Johnson W.M.} HAWES & D.{John DeLooze - Company Secretary} D.{John DeLooze - Company Secretary} RAYNER. September 16th. 13,071. " Means for generating electricity." G.{Mr Griffiths - Chief Accountant / Mr Gnapp} W. MUIR. September 17th. | ||