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to the total cost per unit will give some idea of the effect the number of lamp hours has upon this item.
Rate per unit due to interest, &c. - The low rate per unit in No. 1 (steam plant) is owing to the greater number of hours the installation is run. For instance, if the gas engine plant No. 2 was run for the same number of lamp hours, the cost would be reduced from 2:8d. to about 95d., or a total cost per unit of 1.8d. as against 1.4d. for steam (exclusive of boiler).
Total average cost.-- In comparing the total cost per unit as herein given with the cost of energy from supply company which varies from 4 d. to 8d. per unit-it must not be forgotten that to these latter amounts there must be added an additional sum for interest and depreciation upon the wiring and lamps, also renewals and transformer and meter rent, &c., which has been included in these costs of 1.4d., 3 d. and 3:9d. respectively.
The interest &c. rate is made up of 5 per cent. interest (3 or 4 per cent. might be fairer) on first cost. ; 5 per cent. depreciation, cost of attendance, house rent, repair and renewals of lamps, &c., for portions under test.
No. 1 Plant.—24-unit four-pole compound-wound · Tyne ' dynamo, belt-driven, by Messrs. Ernest Scott and Mountain, Limited; constructed to supply current for 400 16-candle-power incandescent lamps.
No. 2 Plant.—24-unit two-pole compound-wound Tyne' dynamo, belt-driven ; constructed to supply current for 400 16-candle-power incandescent lamps and set of accumulator's for 100 16-candle-power lamps.
No. 3 Plant.—18-unit two-pole compound-wound Tyne' dynamo, belt-driven ; constructed to supply current for 300 16-candle-power incandescent lamps.
No. 4 Plant.—16-kilowatt compound-wound dynamo, beltdriven; by Messrs. Lawrence Scott and Co. Output-152 ampères, 105 volts.
In the driving of dynamos a grave error is often made in the length of belt drive ; people used to steam engine practice look to long drives as the correct thing—with the result that an excessive oscillation and wave motion is given to the belt, which seriously affects the running of the dynamo and the steadiness of the light.
The centres of engine and dynamo should not exceed 18 feet or be less than 12 feet.
CALORIFIC value of coal gas, 197
Dowson gas, 197
types of, 156-157
ous gas, 200
of sunflower seed shells, 208
Thwaite, for driving gas en-
oil drives engines, 202
table of sizes, marine pattern,
Cotter pattern, 91
two and a half times and three
oil gas, 204
carbonising sawdust, 205
table of sizes, 106
Robey pattern, 107
slab type-table of sizes, 81
balance type, 83
tandem engines, 15-16
ABSORPTION, dynamometers to measure
the useful or brake horse-power of
a gas engine, 226-239
twin, gas engine, 5-6
tandem, gas engine, 6
in Dowson gas generator, 198–201
in Thwaite gas plant, 209-214
single cylinder section, 41
tandem 400 B.H.P., 44-46
Robey section, 139
BALANCE of heat supplied to gas engine,
· list of sizes, 52
temperature of, 137
Cycle of operations-single cylinder en- Gas METERS-— Table of sizes, 161
Gas valve and cock, 120
Centrifugal form, Dead weight,
- Inertia, Crossley, 96-98
Vibrating, 'Stockport,’ 101 -102
Arrangement of, 103
Graphic method of determining weight
of fly wheels, 65-70
pressure on pistons, 84-86
strength of shafts, 76-80
HEAT carried off by jacket water in
keeping the cylinder cool, 238
Heat taken up by charge during com-
Rejected in exhaust, 238
air pump. 59
IDLE strokes of the Otto engines, 5-6
Crosby (Section), 176-177
JACKET-WATER, heat list. Measurement
Joints--Combustion chambers, 9, 20, 25,
- Exhaust valve boxes, 10, 25, 35,
Junkers' Calorimeter, 191-197
drive engines, 202
cylinder horizontal engine, 100 B.H.P. | Life, average, of ignition tubes, 140-141
Lubricators for connecting rod, 91-92
cylinder vertical engine, 100 B.H.P.,
Arrangement of, 203
Arrangement of, 206–207
by planimeter, 183
- power of friction brake, 170
Mechanical efficiency of a ga engine,