TRANSACTIONS OF SECTION G. 991 



The diagrams obtained show the maximum load to be 354 I.H.P., the normal 

 load 254 I.H.P., and light load 207 I.H.P. Of this there is lost in engine friction 

 45 H.P. and in shafting 88 H.P. = 133 H.P. The average power used by the tools 

 is 121 H.P. — that is, 48 per cent, of the normal power of the engines. In the case 

 of two of the engines the tools used only 25 per cent., 75 per cent, being lost. 



Power Hequired for Electric Driving. 



Ten motors will be used, ranging from 65 to 2 H.P., driving the shafting near 

 to where the work is taken off. Considerable shafting will be discarded, and the 

 total power developed by the motors will be 76 H.P. less than the present engine 

 I.H.P. 



The new boiler will evaporate 9 lbs. of water per lb. of fuel, while the engine 

 will use 16 lbs. of steam per I.H.P. hour. Allowing for contingencies, the fuel 

 per I.H.P. hour will be 1-9 to 2 lbs., just one- fourth of that used at present. 



The efficiency of the electric system, taking the ratio of the power at the motor 

 puUy to the I.H.P. of the generating engine, is 69 per cent., and 258 I.H.P. will 

 be required as an average. The I.H.P. is practically the same as before, but the 

 saving by the use of an economical engine close to its boiler represents, for reasons 

 ias before stated, 1,000/. per annum. 



The three-phase system was adopted after full consideration, because of its 

 superior mechanical merits and the absence of commutators and brushes, which are 

 troublesome adjuncts of the direct-current system. 



The new plant will consist of one Lancashire boiler, with Bennis automatic 

 stoker and damper regulator, a 96-tube Green's economiser, a 400 I.H.P. hori- 

 zontal compound surface- condensing engine, an Edward's air pump, a 6-inch 

 centrifugal circulating pump, and a Klein cooling tower for the condensing water. 



There will be one 275 JB.H.P. Brown-Boveri three-phase generator and 10 

 motors from 65 H.P. downwards, all supplied by Messrs. T. Richardson & Sons, of 

 Hartlepool. For lighting the works there will be 750 glow and 22 arc lamps 

 grouped on the three phases and run at 110 volts. The motors will be arranged 

 for 190 volts effective. The lower lighting voltage enables the use of more efficient 

 lamps. The wiring will be protected by hard wood casing throughout, and the 

 whole of the work is being carried out by the firm with which the author is 

 associated. 



4. The Electric Lighting System at Bristol, with Special Reference to 

 Auxiliary Plant. By H. Faraday Proctor. 



5. Electric Traction by Surface Contacts. 

 By Professor Silvanus P. Thompson, F.R.S. and Miles Walker. 



TUESDAY, SEPTEMBER l.S. 



The following Papers were read : — 



1. Schemes for the Improvement of the Waterway between the Bristol 

 Channel and the Birmingham District. By E. D. Marten MA 

 M.Inst.C.E. ' ■' 



\ The trunk waterway consists of the tidal Severn estuary for 20 miles from 

 Bristol Avon to Sharpness Docks, thence of the Gloucester and Berkeley 

 Ship Canal for 16 miles to Gloucester, and of the canalised river Severn for 

 42 miles from Gloucester to Stourport. 



It is connected with the Birmingham district by the Worcester and Birming- 



