ELECTRIC LIGHT INSTALLATION.

Pukekohe & Waiuku Times, Volume 5, Issue 195, 28 July 1916, Page 2

ELECTRIC LIGHT INSTALLATION.

PROPOSALS EXPLAINED.

As announced ia our last issui, the Pukekohe Borough Council have included in their loan proposals a ' sum of £SOOO for an electric light ! installation. The report on the project, submitted to the Council by Mr E. J Fenn, consulting electrician, is as follows but it should bo noted that as a result of consultation with the Council (as detailed at the foot of the report) the scheme as originally drafted has been somewhat modified and extended : EXPERT'S REPORT. In accordance with instructions I . haye visited Pukekoho with a view i to reporting on the proposed scheme for an tl ctiic supply with'n | the Borough. Your instructions were to the effect that a small 1 scheme for the centre of the town i should be considered at first, the , power for same being generated by . an existing engine at the pump house, the s -heme to be suitable for ' extending at a later dite to the I remainder of the Borough. In- ; vestigation proves that this is quite . feasible and in fact the most cc >nomical that could b9 arranged in the present circumstances r The area which I suggest thould t be included in the small scheme is , shown on plan accompanying this report. This area 1 hare made somewhat larger than ihat which 1 was suggested to me by the Council ) as it is very desirable to get as many i private consumers connected in the r early stages as passible If the distributing mains be confined to the business streets a large demand ! for electricity would take place on r one day only in the week, that is the r late shopping night, and for the rest of the week the plant would be practically idle, whereas a supply to private houses mesas a steady demand each evetiing in the week. For street lighting I recommend - the installation of 32 lamps of 100 I landle-power and 9 lamps of 300 t He-power, the latter b3ing of the new nitrogen fillel, or as commonly called half-watt type. 5 The positions of these lights are shown on plan. -- The engine at the water works is a National Gas Engine of the E electric lighting type and is quite i. suitable for driving a dynamo. This I e jgine is rated to give out 45 B.H P. t and could therefore generate about 30 kilowatts. Allowing for losses [ in tho line 27 kilowatts would be j available for lighting. Of this [ amount tho street lighting would . absorb 5 kilowatts, leaving 22 for > sale. Each kilowatt would light sixteen 50 candle-power lamps, it will therefore be possible to supply ! 352 lamps alight simultaneously. | AH the lamps would never be alight 1 together, in fact ia the private 1 houses tho number alight at the same time rarely exceeds one-third of the number connected. In the shops, however, all may be alight simultaneously. 1 In the case of the small area under | consideration it would not be practi- ' cable to wire more than twice the number of lamps that the plant is capable of supplying, that is to say, the maximum number of lamps that could be safely connected to your j resent plant would be about 700. The capital expenditure for the small tchcme would be as follows : £. Plant and mains .. .. 251)0 100 service* and meters .. 350 Engiueiringand contingencies 2 ( J4 Total .. .. 3234 When the limit of the capacity of the present scheme is reached it will be advisable to largely extend the power house, and at the same time extend the distributing mains to any portion of the borough in which there is a prospect of sufficient demnd to warrant the necessary capital expenditure. Th 9 exact size of the plant used in the extensions would be determined at a later date when more corruct information as to the probable demand would be available than at present, but for the purpose of estimate I have assumed that an extension of the plant would take the form of:—One 00 kilowatt d.c. generator coupled to a suitable gas engine, together with the necessary producer and auxiliary machinery, and one storage battery. The estimated additional capital exI penditure on such, including extensions to buildings and 200 additional services would be £6711, making a total of £9945. I WORKING EXPENSES AND REVENUE. SMALL SCHEME. The current would only be available during the normal hours of lighting, say, from shorily before dusk to midnight One additional engineer only would be required at the power house. I estimate the btal adlitional labour cj;t will not exceed £240 per annum. Working costs will bo as follows : £. Labour per annum .. .. 240 Coal, 57 tons at £ I .. ~ 57 Oil and sundries .. .. 12 Allow clerical work .. 26 Repair and depreciation, 4 per cent on £3300 .. .. 132 Interest and sinking fund, 0 per cent 198 Total .. ~ (_»6-3 Revenue. £. s. , 700 lamps of 50 candlepower burning an averago of one hour per day, 365 days, wouM use 15,96'.) units j oi" i annum at *d net .. 5j2 6 Street lamps using 5 < units per hour, 5 hours ( por day, would roquire i per annum 912-1 unih i at fid . . ~ ~ 223 fi i

THE PUKEKOHE SCHEME.

Meter rents, say, 100 at 12s per annum .. 60 0 Total .. .. 820 12 Expenditure .. 605 0 Profit .. ~ 155 12 LVRGE SCUEME The 60 kdowatt set, working in conjunction with the battery, would be capable of furnishing current to 1120—50 candle-power lamps in addit'on to the street lamps alight simultaneously, the smaller engine and dynamo acting as a standby only. The number of lamps that could be safely connected up would probably be two and a-half times this number, that is to say, 2800 lamps. This total is not likely to be reached for several years but I think that 2000 limps of 50 candle-power or their equivalent might be expected to be connected up within two years of the installation of the larger plant The current would be available day and night and a demand for supply for motive power would certainly arise. The extent of this demand during the first lew years is difficult to ascertain as it varies very | greatly in different towns. For the | purposes of estimating ttie revenue I t am assuming that motors aggregating 60 h.p. will be connected and that the current required will be ' equal to the motors working two , hours per day at full load. Expenditure and Revenue would be as follows: — Expenditure. £ s. d. Engineer 250 0 0 2 Assist ints at £IHO 360 0 0 i Coal, 150 tons at £1 150 0 0 i Oil and Sundries 30 0 0 Clerical work, say 52 0 0 Depreciation and repairs ' 1 4 per -cent on say i £IO,OOO 400 0 0 i Interest and Sinking ' Fund, 6 per cent 609 0 0 i _____ £lßl2 0 0 Revenue. £ 8. d. i 2000 lights burning 1 hour per night would i use 45625 units per annum at 8d .1520 16 8 ; 60 horse power running 2 hours per day, 300 i days per annum would i use 32,400 units at 2Ad 337 10 0 1 Street lighting 228 6 0 ■ 300 meters at 12s per an- ; nurn - 180 0 0 ' 2266 12 8 Expenditure 1842 0 0 1 Profit £424 12 8 I It will be seen from the above , calculations that it will be possible to make a small profit on the scheme. The figure given is, however, the maximum profit possible as no more lamps than calculated could be connected. This number of lamps, however, should be obtained without difficulty and it is therefore quite probable that the first year's work could be carried on without loss. When a larger demand arises, however, the larger scheme will have to be inaugurated and extra capital N exfeaditure met. The figures given show that with the larger scheme it is possible to make quite a substantial profit over and above all working expenses, allowance for depreciation and interest and sinking fund. It must not be assumed, however, that this profit can be obtained at first, pie working expenses will immediately increase when tho larger scheme is stated as this provides for a supply of current all day and night. I anticipate, therefore, that the first year's work on 1 the larger scheme will probably result in a loss. This loss, however, is not likely to entail any great call on the rates, as the larger scheme would not be inaugurated until the smaller scheme had proved that there was sufficient demand to warrant extension. The larger plant would start wish a fair load which would have been obtained with the smaller plant. Therefore the period of loss is likely to be less than if the larger scheme was started at first. In addition to this, it must be borne in miad that the amount allowed for depreciation will be merely a bookkeeping account for several years, that is to say, although the depreciation has to be a'lowed for na actual money need be provided for such in the early staged. Memo.—For the purpose of this report one Board of Trade unit or kilowatt hour is assumed to be capable of lighting one 50 candle-power lamp for 16 hours. Modern lamps may give slightly better results. The 50 candle-power lamp is taken as the unit as this is the size oilamp most generally in use in private houses. Smaller candle-power taking proportionately less current are usually used in bedrooms, passages, I etc. LIGHTING AREA. The area for the small scheme, recommended by Mr Fenn, embraces the following thoroughfares, viz, King street, East street, Prospect Terrace, West street (to Jackson's Corner), Harrington Avenue f DuVsin street, Seddon street (to "JUnnaa Catholic Church), Edinburgh street, •: Albert street, Tobin street, Hall street, Manukau road v to Horso Bazaar), Harris street and Quoen street (to Domain). COUNCIL DISCUSSION. In the course of the discussion at the Council meeting on Monday last, Mr Fenn, in reply to questions explained that the storage battjry v or accumulator) stores up the amount of current which the engine may he producing over and above nliat is being used by customers at