May 30, 1913.

______________________________________________________________________________________________________________________________

THE COLLIERY GUARDIAN.

1127

at all speeds. These machines should have ratings specified
for both minimum and maximum speeds.

(6) Test rating and pressure variation: Guarantees as
to heating, efficiency and other characteristics are to be
taken as applying to tests at the pressure marked on the
nameplates, but motors must be capable of operating
without injury at their rated outputs and overloads on any
pressures not exceeding 5 per cent, above or below their
standard prassures. It should be noted, however, that the
** pull out ” torque or maximum torque available will vary
approximately as the square of the terminal pressure.

Section V.—Overloads.

(1)	(a) Machines with continuous rating having limits
of full load temperature rise in accordance with Section VI.

(a)	are to be capable of withstanding 25 per cent, overload
beyond the continuous rating for the following periods :—
100-kw. or h.p. and above ................ Two hours.
Below 100-kw. or h.p., not below 25-kw. or h.p. One hour.
Below 25-kw. or h.p., not below 2-kw. or h.p. One half-hour.
Below 2-kw. or h.p........................ Five minutes,

(6) Machines with continuous rating having limits of
ull load temperature rise in accordance with Section VI.

are to be capable of withstanding 15 per cent, overload
beyond the continuous rating for the periods shown above.

(c) Machines with continuous rating, of the “ totally-
^nclosed” class, having limits of full load temperature rise
in accordance with Section VI. (c) have no overload ratings
except the momentary overloads required in connection
with commutation tests.

The above overloads are to be measured in kilowatts,
kilovolt-amperes, or horse-power according to the name-
plate, except in the case of series or compound motors for
which the overlands should be measured in amperes of
input.

(2)	With machines having two or more fixed speeds the
above overload ratings are to apply at each speed. With
variable speed machines having ratings at minimum and
maximum speeds, the above overload ratings are to apply
at each speed. With machines having a speed range
exceeding 2 to 1, and the same ratings at all speeds, the
above overload ratings apply at any speed from the
minimum to 75 per cent, of the maximum speed.

(3)	Motors with short-time rating are to be capable of
/Carrying an overload of 100 per cent, torque for 30 seconds.

(4)	Transformers are to be capable of withstanding over-
loads of 25, per cent, for two hours, and 100 per cent, for
30 seconds.

Section YI.—Heating.

(1)	Determination of Temperature Rise—The temperature
rise of electrical machinery, both rotating and static, is to
<be taken as the difference between the cooling air tempera-
ture as defined in clause 6, and the temperature of the
machines after giving their normal rated output for the
following periods: —

(а)	For machines with continuous rating. Until the
temperature rise is practically constant—that is, until the
rate of increase of temperature rise does not exceed 1 deg.
Gent, per hour. (This condition will usually be reached in
less than six hours, except in the case of oil-immersed
transformers.)

(б)	For machines with short-time rating. After working
-continuously for the period defined by the rating.

(2)	Permissible Temperature Rise.—For machines with
^continuous or with short-time rating and designed to
operate under ordinary conditions of cooling, i.e., designed
for an air temperature of 25 degs. Cent. (77 degs. Fahr.),
the following temperature rises are the highest permissible
At the normal full load:—

(a) Machines Having Unobstructed Ventilation.

(Section III., Classes 1, 2, 3a, 4a, 4b.)

Rise by thermometer.

Jill windings ............ 40 degs. Cent. (72 degs. Fahr.)
•Cores in which windings

are embedded.......... 40 degs. Cent. (72 degs. Fahr.)
-Commutators and sliprings 55 degs. Cent, (99 degs. Fahr.)

In general the temperature rise by increase of resistance
^should not exceed 55 degs. Cent. (99 degs. Fahr.) for
Alternator field coils, or 60 degs. Cent. (108 degs. Fahr.) for
shunt field coils of direct-current machines in this class.

(b)	Machines Having" Partially Obstructed
Ventilation.

(Section III., Classes 3b, 4a, and 5.)

Rise by thermometer.

AH windings ............ 47 degs. Cent. (85 degs. Fahr.)
Gores in which windings

are embedded.......... 47 degs. Cent. (85 degs. Fahr.)
Commutators and sliprings 55 degs. Cent. (99 degs. Fahr.)

In general the temperature rise by increase of resistance
should not exceed 65 degs. Cent. (117 degs. Fahr.) for shunt
'field coils of direct-current machines in this class.

(c)	Machines of the “Totally-enclosed” Class.
(Section III., Classes 3c, 6, and 7).

Rise by thermometer.

AH windings ........... 55 degs. Cent. (99 degs. Fahr.)
Cores in which windings

are embedded......... 55 degs. Cent. (99 degs. Fahr.)
Commutators and sliprings 55 degs. Cent. (99 degs. Fahr.)

In general the temperature rise by increase of resistance
should not exceed 70 degs. Cent. (126 degs. Fahr.) for shunt
field coils of direct-current machines in this class.

(3)	Transformers.—The temperature rise of transformers is

to be measured at their rated full load output, under the con-
ditions specified in clause 1. It is permissible, however, to
reduce the time of test by running for a time on an over-
load in current and pressure, then reducing the pressure to
normal and maintaining at this until the required standard
rate of temperature rise is attained. The limit of permis-
sible temperature rise at the rated full load is as follows :—

Oil-cooled—	Dege. Cent.

By resistance or by thermometer in the oil ...	50

Air-cooled—

By resistance or by thermometer ..........	50

(4)	Machines for Tropical Conditions.—For tropical con-
ditions or other cases where the cooling air temperature is
in excess of 35 degs. Cent., the permissible temperature
rises shown in the preceding clauses are to be reduced by
20 per cent. This does not apply to machines insulated
with special heat-resisting materials in accordance with
clause 5.

(5)	Special Heat-resisting Materials.—The limits of
temperature rise shown in clauses 2, 3, and 4 above, apply
to windings whose insulation consists wholly, or in
important part, of cotton, paper, varnished cloth, or similar
materials. Higher temperature rises are permissible in
the case of windings where asbestos, mica, or preparations
of these materials are solely relied upon for insulation.

(6)	Measurement of Cooling Air Temperature.—The air
temperature is to be taken as the mean of the temperatures
measured at regular intervals during the last quarter of the
test period. When the machine under test is provided
with pipe ventilation or forced draught, the air temperature
is to be measured by a thermometer placed in the current of
incoming air. In the case of machines other than those
referred to in the preceding paragraph, the air temperature
is to be taken as the mean of the readings of two or more
thermometers placed not more than 6 ft. from the machine,
and on a level with its centre on opposite sides. So far as
possible, these thermometers should be placed so as to
measure the current of air flowing towards the machine
but they must not be exposed to radiation or stray
draughts.

(7)	Correction for Altitude.—When a machine is intended
for service at high altitude, the permissible temperature
rise, if tested near sea-level, is to be reduced 2£ per cent,
for each 1,000 ft.

______________________________

THE TIN-PLATE TRADE
Liverpool.

Enquiries have fallen off the last few days, and business
all round has been very quiet. The tone of the market
is easy, and prices without material change. Makers’ quo"
tations are about as follow:—Coke tins, IC 14 x 20 (112 sh*
1081b.), 14a. 3d. to 14s. 6d. per box; IC 28 x 20 (112 sh
216 lb.), 29s. to 29s. 6d. per box; IC 28 x 20 (56 sh.
1081b), 14s. 9d. to 15s. per box; I C 14 x 18f (124 sh.
1101b.), 14s. 9d. to 14s. lOjd. per box; IC 14 x 19| (120 sh.
110 lb.), 14s. 9d. to 14s. 10|d. per box; IC 20 x 10 (225 sh.
156 lb.), 21s. to 21s. 3d. per box; IC squares and odd sizes
in approved specifications 14s. 9d. to , 15s. basis. Terne
plates are quiet at round 25s. for I C 28 x 20 unassorted.
Charcoal tins are in moderate request, and quotations run
17s. 6d. basis and upwards according to tinning. Coke
wasters meet with a fair enquiry, and are quoted:—C W
14 x 20, 13s. to 13s. 3d. per box; C W 28 x 20, 26s. 9d. to
27s. per box ; C W 14 x 18f, 12s. 9d. per box; C W 14 x 191,
12s. 10|d. per box; C W 20 x 10, 18s. 3d. per box—all f.o.b.

i Wales, less 4 per cent.

______________________________

Proposed Mine Surveyors’ Institution.—Prof. Henry
Louis presided over a meeting of Northumberland and
Durham colliery surveyors, held at the Armstrong College,
Newcastle, last Saturday afternoon, for the purpose of
considering the advisability of forming an institution of

colliery surveyors. The chairman stated that the proposal
was of importance in view of recent legislation, which he
welcomed as being the outcome of an agitation he started
about 15 years ago, when he felt that it was necessary that
mine surveyors should produce evidence of their qualifica-
tions. The recent Act was going to alter the position of
mine surveyors considerably, because, in the past, experience
in surveying had been allowed to count as practical
experience in sitting for a colliery manager’s certificate
Now that was stopped, and the ultimate result for colliery
surveyors would be that they must start and remain
as colliery surveyors. It was, therefore, desirable that they
should get their calling more fully recognised, as it would
tend to become more important, instead of being, as now, a
short cut to management. They ought to make their

influence and importance felt, and take steps to protect
themselves and to raise the status of their profession. Mr.
Lockerbie stated that the meeting was really a preliminary
one for the exchange of views. It had been suggested that
they should become a fourth branch of the Surveyors’
Institute. Another suggestion was that they should form
a national society of their own, having both a scientific and
a protective side, much on the lines of the Colliery
Managers’ Association. Several of those present expressed

themselves in favour of a separate national institution, and »oxygen cylinder may with advantage be reduced in
that was decided upon by a unanimous vote. A committee weight, irrespective of its capacity. The apparatus
was appointed, with instructions to communicate with |8atisfie8 the solitary requirement imposed by the Minis-
leading surveyors m other coalfields asking them to hold \	~	,..

meetings in their districts in order that the feeling of i tenal Order of Apnl 15,1907 namely, that of enabling
colliery surveyors nationally might be ascertained.	I the wearer to continue for at least an hour in an

— PROGRESS. —

The Direct Production of Sulphate in the
North of France.

At the Lens Colliery, No. 8 pit, the Koppers semi-
direct process of purification has been adopted. At this
pit the coke ovens were of an old pattern, and it was
desirable that the arrangements should be as simple as
possible. At Dourges the Feld direct process has been
adopted. In the Pas-de-Calais the number of ovens in
operation has now risen to 1,518, of which 226 are of the
by-product type, with regeneration, 1,014 of the by-
product type, and 278 of the beehive type. In 1911
1,920,467 tons of coal were carbonised, and 1,468,176
tons of coke made.

______

The Utilisation of Coke-oven Gas in the Ruhr
District.

According to particulars compiled some time ago by
Dr. Jiingst for Gluckauf, in 1903 only two mines in the
Ruhr district supplied coke-oven gas for lighting
purposes, producing 393,000 cubic metres of such gas.
The development of this branch of industry, however,
has been rapid, the output of gas in 1910 amounting to
42,059,502 cubic metres from nine collieries. As a con.
sequence many towns situated, not only in the confines
of the coalfield but also, as in the cases of Gref eld and
Barmen, at some distance from it have closed their local
gasworks in favour of a colliery supply. At the same
time there has been a great extension of the use of coke-
oven gas for the production of electric power at the Ruhr
collieries for their own needs. Thus the total output of
electrical energy has risen from 58,274,000 kw.-hours in
1906 to 461,578,000 kw.-hours in 1910; or, adding the
energy produced by means of blastfurnace gas, from
104,013,000kw.-hours to 567,337,000 kw.-hours in 1910,
In 1910 the production in 1,000 kw.-hours of the
principal companies was as follows:—Gelsenkirchen,
58,701; Hibernia, 43,917; Harpen, 41,154; Gutehoff-
nungshiitte, 41,154; Phoenix, 12,132; Fried. Krupp A.G.,
7,362; Mulheimer Bergw. Ver., 5,600. The power is
consumed in the main by the companies for general
purposes at their mines, steelworks, &c.; but a certain
quantity of current is also supplied to other consumers,
the proportions in 1910 being as follows:—Collieries,
401,654,000kw.-hours ; companies’ works, 37,515,000 kw.-
hours ; other consumers, 22,410,000 kw.-hours. Taking
now the energy produced from blastfurnace gas,
69,028,000 kw.-hours were consumed by steelworks,
32,202.000 by collieries attached thereto and 4,529,000
by other consumers.

______

Nitrogen in Coal.

According to a note presented by K. Bunte to the
Karlsruher Chemische Gesellschaft, the content of
nitrogen in coal varies considerably. Thus:

Per cent, of nitrogen.

Containing Average.

ITO to 168 ... 1’45
1T4 to 1*51 ... 1'30
1T9 to 1'81 ... 1'50
1'35 to 2'0	...	1'80

1'85 to 2'10 ... 1'95

rather higher in coals that

10 Saxon coals......

21 Saar coals........

18 Westphalian coals

26 Ruhr coals ......

15 English coals ....
The content of nitrogen is

have been raised for some time than in those freshly
wrought. On the average, after distillation, 50 to 60
per cent, of the nitrogen remains in the coke, 3 per
cent, in the tars and cyanides, 15 to 25 per cent, in the
gas, and 10 to 20 per cent, in the ammoniacal liquor.

______

French Report on the Fleuss Apparatus.

A recent number of the Annales des Mines (Vol. III.,
2, 1913) contains a report to the French Permanent
Firedamp Commission on the Fleuss (Proto) rescue
apparatus, by M. Taffanel, the director of the Lievin
experiments station. He considers that the apparatus
is a good one, and it is to be commended on account of
its simplicity, as well as the ease with which it can be
controlled. Its operation is immediate, and the
amplitude of the breathing bag and the by-pass arrange-
ment give guarantees against lack of air in the event of a
momentary excess of work superior to all other existing
appliances. Other good points are its lightness, the
commodious arrangement and the ease of circulation.

The chief defect, M. Taffanel considers, resides in the
excessively high temperature of the inhaled gas,
which workmen accustomed to the use of the Tissot
apparatus found to be troublesome, and, judging
from the sample apparatus tested at Lievin, care
should be exercised in seeing that the appliance is air-
tight before delivery. He considers further that the