The Diseases Of Electrical Machinery
Forfatter: Ernst Schulz
År: 1904
Forlag: E. & F. N. SPON, Ltd.
Sted: London
Sider: 84
UDK: 621.311
Edited with a preface, by Silvanus P. Thompson
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50
THE DISEASES OF
running, since the losses in the machine disappear as
heat. The rise of temperature under normal circum-
stances must, however, not exceed a certain amount,
and it has been fixed, from long experience, that the
heating of any part of the machine in continual work
should not exceed 40° Centigrade, or 70° Fahrenheit,
above the temperature of the surrounding air.
In order to see whether the temperature-rise, after
several hours’ running, exceeds the above limit, it is
not sufficient to feel the machine with the hånd.
Special thermometers must be placed on the arma-
ture winding immediately the machine is stopped, and
prevented from cooling by cotton wool or wadding.
The readings must be taken at short intervals, and
continued until no further rise of the thermometer can
be observed, i.e. until the thermometer begins to fali.