TRANSACTIONS OF SECTION G. 679 
and which also supplies practically the whole of the manufacturers on the north 
bank of the Tyne, is the Carville power-station of the Newcastle-upon-Tyne 
Electric Supply Company, Limited. This station supplies power for probably a 
greater variety of purposes than does any other station in present operation, Its 
equipment consists of 20,000 horse-power of plant, made up of Parsons’s turbo- 
alternators, two of which are of 7,000 horse-power, being the largest steam turbines 
yet constructed in this country. 
Conclusion.—The ideal arrangement for power supply is, the authors suggested, 
that by which all the electrical requirements of an industrial neighbourhood are 
supplied from a single inter-connected power transmission and distributing system. 
Such systems are commercially possible in this country, due to (1) its density of 
population ; (2) its cheap coal supply ; and (3) the nature of its industries, and 
the waste power which is naturally produced by them. 
On all load factors up to 30 per cent. a saving of 1/. per kilowatt on the 
capital expenditure has greater effect on the selling price of current than the 
reduction of the coal bill by 6 per cent. (coal being taken at 6s. per ton). It is 
therefore evident that if a steam station can be erected so as to cost 17/, less 
per kilowatt of plant than a station driven by water-power, electricity can be sold 
more cheaply from the former than from the latter. In fact, it is probable, absence 
of water-power notwithstanding, that this country could be supplied with electrical 
energy more cheaply than any other country in the world. 
3. Testing Alternating Current Induction Motors by a Hopkinson Method. 
By W. E. SumpNer and R. W. WEEKES. 
4. Energy Losses in Magnetising Iron.? 
By W. M. Morvey and A. G. Hansarp. 
The authors called attention to the magnitude of the total amount of enere'y 
lost in magnetising iron in electrical machinery, estimating that in this country 
alone between 25,000 and 50,000 tons of coal are expended annually in keeping 
transformers magnetised, without including the magnetising losses in the armatures 
of alternators, dynamos, and motors. 
The total losses, as measured by a wattmeter, in different thicknesses of iron of 
the same quality at different periodicities, are compared amongst themselves and 
with hysteresis tests made by other methods, and also the total losses in the same 
sample of iron at different temperatures, and the following general conclusions 
are arrived at: (1) In determining the magnetic quality of iron sheets, eddy- 
current losses, though often neglected, are by no means negligible, and are often as 
important as hysteresis; (2) the simple laws generally assumed to be followed by 
hysteresis and eddies are found, as often as not, to be rather widely departed from 
—e.g., the total loss of energy, including eddies and hysteresis, often does not follow 
a B’° curve; and (3) consequently, with such a variable material as iron, the only 
satisfactory method of predicting losses is to make wattmeter tests of samples as 
nearly as possible under the working conditions. . 
Fig. 4 shows the total loss (hysteresis and eddies) in three thicknesses of iron— 
viz., 0136 inch (‘34 mm.), ‘0189 inch (-47 mm.), and ‘0254 inch (61 mm.), This 
iron was all of one make. It was tested in transformer form at 50 periods and 
100 periods per second, and at magnetisations suitable for transformer work and, 
to some extent, fordynamo work. The tests were made on an alternator having 
practically a sine curve. The samples were large—nearly 12 Ib. each—the total 
1 Published in the Electrical Engineer, August 26, 1904. 
* Printed in full in the Electrical Engineer, August 26, 1904, N.S. xxxiv. p. 297, 
and in the Electrician, September 2, 1904, lviii. p. 790, 
