THE COLLIERY GUARDIAN

AND JOURNAL OF THE COAL AND IRON TRADES.

Vol. CV.

FRIDAY, APRIL 25, 1913.

No. 2730.

THE ELECTRIFICATION OF CANNOCK CHASE
COLLIERY.*

By S. F. Sopwith.

Introduction.

As electricity has not been adopted to so great an
extent at the collieries in the Cannock Chase district as
in some others, a description of the plant now at work
at Cannock Chase Colliery may be of interest to
members.

Seeing that the effect of additional legislation was to
increase cost of production, it has become essential
that modern methods should be introduced into the
older collieries if the all too narrow margin which

the scheme, which has gradually been extended in other
directions.

The writer wishes at the outset to explain that this
paper is not meant to be of an electrically technical
character, but simply a brief summary of the plant, and
to set forth the economy and advantages derived from
the adoption of that form of power.

Power Station.

Steam at a pressure of 165 lb. per square inch is
raised in two Lancashire boilers measuring 30 ft. by
9 ft. 3 in.; a third boiler of similar capacity is provided
as a stand-by, and a fourth is in course of erection. The
steam is superheated 100 degs. Fahr. Feed pumps of the

redwood poles, to sub-stations at Nos. 2, 3, 7, and 8
pits, where it is transformed to 600 volts. Lightning
arresters are placed at the power station and sub-
stations and at one point between the two.

No. 2 Pit Sub-station.

The plant at this pit at present consists of a 100 kw.
transformer of the core type, stepping down from
3,000 to 600 volts. Current is supplied underground
for a 75 brake horse-power motor that drives the main
endless haulage gear, and two 10 brake horse-power
portable haulage gears; on the surface for a 20 brake
horse-power motor that drives a creeper and screen-
conveyor of the Marcus type, for a. 20 horse-power

75-horsb Power Motor Driving Haulage Gear through
Epicyclic Reduction Gear at No. 2 Pit.

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40-horse Power Motor Driving three-throw Pump at
No. 3 Pit.



70-horse Power 3,000-volt Main-and-tail Haulage Gear.

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180-horse Power 3,000-volt Main-and-tail Haulage Gear.

normally exists between costs and sales is not to be
reduced to vanishing point. The aim of the colliery
manager to-day is not so much to reduce costs as to
maintain them at their present level, despite the ever
increasing burdens which the exigencies of the times
put upon him.

It was on this account that the Cannock Chase
Colliery Company decided to adopt electricity, with a
view to reducing colliery consumption and providing a
means of transmitting power underground for haulage
and other purposes. The substitution of electric drives
for the screens and picking-belts formed the nucleus of

*A paper read before the South Staffordshire and
Warwickshire Institute of Mining Engineers, April 21, j
1913.

Weir type pump hot feed-water |to the boilers through
a Babcock and Wilcox heater, the heat being obtained
from the exhaust of the engines, which passes to the
atmosphere. The generating plant consists of three
direct-coupled steam alternators, two being of 200 kw.,
and one of 500 kw. capacity. The engines are compound
and triple expansion respectively, and together with the
alternators were made and supplied by the Brush
Electrical Engineering Company Limited, of Lough-
borough. The switchboard is of the Ferranti remote
control type. Three-phase current is generated at
3,000 volts and 50 periods.

Distribution.

The current is carried from the power station by
overhead bare copper conductors, supported on creosoted

motor that drives the sawmill, and for a 20 horse-power
motor that drives a crosscut saw for cutting mining
timber. The 75 brake horse-power motor is worthy of
mention. The motor was applied to the crank shaft
of the old steam-driven gear through epicyclic reduction
gear, the ratio of speeds being 960 to 90 revolutions per
minute. This gear, known as the “ Whitehall,” and
made by Messrs. Strachan and Henshaw of Bristol,
serves the double purpose of reduction gear and clutch,
the motor running continuously.

No. 3 Pit Sub-station

Two transformers of 100 and 50 kilowatts capacity
respectively supply the cun-ent for two 20, one 40, and
one 5 brake horse-power motor for driving the screens
and picking belts, these motors having replaced numerous