1904 electric mine

8/10/2019 1904 electric mine

1/16

: - ' t r r r e ~ r i N T : I,

ltrtrir l

~ i n i n g

~ a r b i t t t r J .

INTROD

UCT

ION

.

Ta

e

appli

cation

of electricity

to

coal-mining machinery

in this country has

made

great

strides

during the last few

years.

Its

adoption

in

our m ine3 came considerably

later than wa.s the case either on

the

Continent

or

in

A

merica; but since the

st l.rt the

progress

has

been fast.

The

number

s of

collieries in Great Britain which

arc

now

ma k

ing

u

se of electricity is large. Pr actically the on

ly

direction in which

this

form of power is

not

employed

extensively is in winding

a.od

main ver.tilation. Possibly

this

may come in time,

but

at present there are

but

few

by

its

aid constderablc sM ing

in

production

is

obtained.

mulator

s,

or faulty main

s.

From

a number of

most

Th ere arc dra"

backs,

without doubt. to its use,

but

these interesting c

xperim

c

nt

Pcarried out by 1\Ir. Wm. Charles

are nothing when com pared to the ad\'antages to be

)fountain-of

Mesers E r n e ~ t

Scott

and Mountain,

looked

for. Such is evident ,, the

opinion of

the members

Limited, of ewcastle-on behalf of

the

Departmental

of

the Departmental Committee

which has been consider Committee,

with

electric

motors running

in explosive

mg the

use

of electricity in mines, an d whose report. has mixtures,

it

appeared

that

C\'en with an open-type motor

tcccntly been

issued. One

sentence of

this

report we 111ay r.parking

badly the

mixture had

to

reach

the

strength

of

quote:

- " When ,

therefore,

W

being

most beneficial

and

in lighting, pumping, hauling, coal cutting, and in working

nccel'lsary to

the safe use

of this

form of

enetgy. There

the other munifarious

machine -

and apparatus at bank

arc

other rules

'uggcs

ted,

how

c

,er, which it

is

thought

which go

to

form

th e equipment of a

modem

collier,,.

by

our

manufacturers and

u

sers-all of whom arc

most

I t

is

the purpose of

this Supplement

to lay before

our anxio

us to do

ever.vthing

"hich

may

conducc to

the

St\

fct,r

readers some

few

details of these ' '

urious application

s o{ of the miners-wiJI not only not

do

good, but may pos

elec

tri

city, and to diecuss the advauta.ges offered by this s ibly

do

harm by hampering the industry. Ho wever, e

form of

pow

er. understand

that

the

1I

on1e ofOce is being

Twent

y years

ago it would

have

been hard to

convince inHuentiall.r approached, and we ha\ c e ' cr,v renHon

to

a

colliery manager

that

any but

the methods he had been hope

that

the final

rules, ' ~ h e n issued,

will

be

acceptable

brought

up

to

were of

any

value. Now, howc,er,

to all.

conditions hM

e

altered.

Econom.Y is Roug

ht

for in every J

n

the early days of

elcctricttl

engineering there \\ere

direction, and the desire

to produce cheaply

has

in th e

too

few r e a l l ~

mechanical engineers who

interested them

majority of instances

oYercome

consenatis

m.

l\Iore- "ehcs in the

design

and manufacture of

electrical

plant.

over,

the

younger generation

,

ns

it

ha

s

grown up,

hac;

Thi

->

stigma

has

long been remo\

cd,

and now electrical

I

\

the

sa.me

condition

ran (or three-quarters or an hour

irt

a mi.xture of 8 to 1 without the mixture being ex

ploded.

t

was

also

started

and

stopped several time l

in rapid

succession,

again without explosion . The current

on these occasions

wall of

course, considerably

in

excess

of

the

normal,

and there w

ai

consequently excessi\'G

sparking .

These experiments ha'

o

hecn co n

firmed

by

othe

r '

,

and

it

ould appear,

the>rcforc,

that

one of

the chief

reasons

for

noL using electrici

ty is, to a gtcat extent,

remo,cd.

\\'ith

so

much preface, we can

proceed

to

describe

,arious types of machines "hieh are now at use in

ou

r

mines.

In

doing so we ha'e to acknowledge

our

in

debtedne

ss

to

the various

makers

who

have pro"ided us

with

the materials and information

which

we are

now

able to

lay before our

readers. In

a case of this kind

it

is impo isible to mention c, cry malown a pit machines are constantly

I

Electrical

coal

winding ha \

n o ~

been practised In t h i ~

end

the electrica.lly-driven

coal cutter has

large

ly co

n

being subjected to

nuntberlcf s strains

which

.

above

c>otmtry

to the

same extent abroad. There is a

wide

tl'ibuted, but

the result is also due

in

some measure to all

ground would only

come

upon

them

very exceptionally. spread

feeling

thnt

it

would not pay

to

disc

ard the excel

th e

use

s to

wh ich electricity

is

put

in

the mines, and

to

the

All

coal-mining machinery should

be

capable of

being

lent steam engines now employed in

nearly

every

more

efficient haulage, pumping, and lighting

thereby

I pulled up

short without

damage.

A fall of roof

or any

inAtance.

Po

ssibly, ah;o, there

is

a certain

dist

ru st

of

things

olJtained.

< ~ i m i l a r

obstruction may suddenly stop a haulage system, electrical which remains ftom early times an d prevents the

El ectricity offers a

number of

advantaaes

for work in

f

or example.

Again, in damp

mines, trouble may be

met uc;e

of electrical

mA.Cbinery in this

direction. Be

this as

it

coal mines. Perhaps

t

he chief of these fs the

ea-.e

and "i th in the

f

onn

of

water. Thiq i < ~

a

contingency only may, the fact remains tl11it

on ,,

in

a

very limited

numbe1

economy with

which it

can

be comeycd and

utili -.ed to 'er) remotely

possible abo,:e g r o ~ n

.

of

instances is

electric

"indiog resorted to. However

1

fa.r-off

points, and position

s to which it

would be

well nigh When the use of electnc1ty m .

coal

mm es

was

fin,t we are enabled to desert

be

one plant, at all e v e n t ~ : -

nnpossi ble to take

any other

form

of power economicallJ. mooted,

a

great deal

of

~ t r e s s "

a" laJd on the ?anger from ,.,.Juch

has

been

at work in thi

s country for some

Th e

n,

too,

it is readily t c d to ditl'cring condWons, and explosion due to

p a r k i n g ,

whether from sw 1tches, com tunc, and )la...

ghen,

so we understand, e\Cl,\


2/16

11

b&.tisfaction.

The

installation

in q u e ~ > t i o n ib

at work

in

the

Y

ictona

Ptt of

the

lleckmondwike Collieries

C o m p a n ~ Limited

.

The cam

being worked i .. called

the

Low :\Ioor Black Bed. Tbc winding plant became

necessan

owing

to the

cropping m of a h u ~ > e ..

fault

or ' th rO\\

,..

about

1000

yard

from

the

pit bottont.

H

ere the ~ e t \ l l t ib

thrO\\ 11

dO\\

n a

'ertical depth

of

60 yard from

the

original le' cl. In order to et at

the

lowet portion of this seam.

it.

was found ~ e c e ~ " a r \

c ~ t h c r to drh c a _large inclined drift or to sink a ~ S t a p l e

ptt. Had

the

dnft been dcctded upon, it would ha'e

-

I

-

>

THE ENGINEER

diameter. The pit

top

is fitted with Callers or keps,

the

whole being

arranged exact

ly ab in ordinary cases. The

winding gear ewpl o,Yed ib shown in Fig. 1, page i. t

i

said to be capable of raising from 1.30 to 200 tons

per

d

ay

of 10 h o u r < ~ .

On the tmrface there is a horizontal singlec;.linder

engme,

the

C,\

tinder being 16in. diameter b,\ 36in ... roke.

The ...

team

pt'Ct'Sure

i-; :;o

lb. per ~ - o o q u a r e inch, and

th

t

iron.

There are two brake

one

of

the

ordinar.}

btuHl

type,

and th

e other, which ma.' be

seen at

the

lefthund ~ i d e of

the engrtning,

is

\\

orked

electrically, and it come;. into action immediately the

curri

in

itR turn engages with the toothed

\\heel on the drum .,haft. From the end of the shaft is

tlllien a. t'mnll extension spindle which i pro\'id

ed with

a

won11. This

worm works into a wom1 wheel fixed at

th

e

lower

end

of

the 'ertical

spindl e of a re ,

olution indicator

ju

..

t

ns in ordinnry colliery \\'inding practice.

The

h a s ~

p ~ a ~ e of the mtlchine is made up of cast iron girders -;ub

dl\

1ded for

cas.}

o . n < ~ o l ' t , and to enable

the 'ariou-;

pot'tions

to he more

readily lo

ered down a.

shaft.

The

motor

i l l ~ t s t r ? - t e d

is of

the

1 a s e

induction type,

with

a shortCircutted rotor.

t

1s

sru.d to be ca

p

able

of giving

out 40 brake horsepower when running at a. speed of

750 revolutions

per

minute. The motors can be

st a

rted

li g

ht

, th ereby doing away with complicated switch

gear. On starting,

the

friction clutch is

out

of gear, and

all

that

the motor has

to do is to

turn the

belt

and

the

loose pulley on

the

countersha.ft.

The double

crown

-


3/16

. l . ~ E 2-f, 190-l

- .

ELE

TRl

A L

SUPPLEMENT

clutch is

then

thrO\\ n

to

whichever side 1t

ib

desired,

th

e in Fig. 4 below.

t

is installed at the Dean

and

only it is belt dri,en on to pulJeys en both

side;

friction clutch is gradually closed,

and

the motor takes Cha

pter

Colliery, near Ferryhill in Dwham, belonging to of a cross shaft.

Th

e

pump

plungers ba ,e a

diameter

up the load. Starting

and

stopping is brought about by

~ l e l s r Bolcko ,

\' ughan, and Co., Limit ed. It is dri, en of 6in. with a

..

troke of 12in. The) arc designed for

means of a switch worked by foot from the driving plat b.' a thn cph'\c;e induction type motor of 100 horse-power de}i,e ting 150 gnllons per

minute-9000

gallons per hour

- - - - - --

----

I

I

I

I

l

-

- - - -- - -

J

form,

and th

e whole

may

be

temted

a workmanlike and

compact piece of engineering design.

PUMPING

PLANTS.

Messrs. J

..

r

ncst Scott and

Mountruo possess

the great

advantage as manufacturers of electrical mining machi

oer ,y

in being also maker of

the

engines to

dri,

e the

generators,

and

of the' arious geats and appliances which

Fi

( .

4 - HORIZONTAL M INI NG PUMP FOR ELECTRIC

DRIVING

nnd

OO

'olt:- per

phal-le.

The petiodicity is 50, and it

rulllo at

5 0 re\ olutiom1 p

er

minute.

The

lllotor fitted

with O at the Broughton and

Pla

b P

o

er Collier

.",

is


4/16

l V

in Pig. 7, belo''. This h n com pact plant, and i,

o sub-di,iclcd

in

con ...

trucllon

- ns, mdecd, are all

the

pmnps

made

h.\ this finn- thu.t

there

is no difficulLy in

getting it in pieces do\\ n a -.haft. no lllt\tter how snHI 11

this

may be.

ThiH

set, a ~ l \ i n has three bttrrcls, each ;)iu.

' diameter and

ha\

ing

tl

7in ... roke.

H

i

..

capable or

deli\

ering

0 g1tllons

per

winute again ...t tt head of

:l:JOft.

hen runumg at, approxnuately, .;; re\

olutions

pet'

minute. The

pump

i1:1

dri' en through clouble reduction

I

I

I

I

THE EN G

I N E

ER

eou1pound enclosed engine of 330 mdicated horse

po er

dri,

ing d1rect a :lOO-kilowatt oix-pole

generator

of the

same \'

OI tage

ns the foregoi11g; one :lOO

brake

horse

pO\\

er

motor; two 150 brake horHe-power motorH;

two

cnd_lesH

rope haulage gears for opemting three roads;

tbc

vanou i

pump ing 1110tors to which e ~ M C ulluded, _and . f'?u r

7 bor"c-

power

motor-., these bemg euplo.' ed

10

dn\'lng

machiner,\, including the K c r e c n ~

at bank.

.

A compact little double centrifugal pumpmg plant b.'

.J I \ E J, 190 I

the

e n g r a n n g - ; - c o n n e c t i u ~ it to the other pole or the

circuit. The d1pper

plate

1s

attached

to

the

rod work1ng

in the vertical guide. Thh; rod

ha s

.o. piston fitted to 1t,

which is

pressed

upwardH by : ~ o p n u g . f the an.dle

lb

drawn to one side or the other,

1t

p u l l dO\\ n th1., p1ston,

d e p r e ~ s i n g the plate into the liquid, and if the

hawlle

let go. it Hies back, due lo

tbe

pressure of the

1

pnng, to

the olfpo,ition. Thert 1s a. small lockmg catch\\ luch

can

be seen on the top

of

the connecting link, ''"hich

holds

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- - - - - - - -

- - - - - - - -

Fie. 7- MOTOR DRIVEN T

HREf

T HROW M INir \0

PUMP

gearing

by an 11 brake hotsepowcr motor of MeR ;rs. the same firm is shown in Fig. 3, page

ii.

Thls is at

Sco

tt and Mountain's Class S

type.

The motor

has

four work

at

the Langle.v

Park

Colliery of the Comett

lr

on

p o l e ~ ; , and

is

what is tenned seH-contained--tbat i;,, it ht\S

CompanJ.

Limited. The motor, which is of the entirel,)

no

need of an ou tside bea1-iog,

l>oth

bcaringb being carried enclosed t,\ pe, gi,es 20 orakc horse-power at 950

re ,

olu

in

the end covers. t runs at970

re,olutions

per JUinut

maller plate

po er,

and

are ouml for 1

-30

'olt -1 direct current. The y

is insulated from

thi

s, and has a tenniual - not S

hO\\

n

in

1

arc

o

the four-pole entirely open

and

l 'C' oh e

at


5/16

J l Xt: 190 I

-00 re\olutionc; per 111inute. The.' dri' e the pumps b.\

rope.

and run

aL 4-iO re\ oluLion the euned

internal

passages

between the

\ anc3,

a1d

is d i ~ c h : . a . r g e d t

ange

ntially

at tho

l

At this colliery

also

this firm has

installed

a

large

amount of

plant

which

is

of intereRt because it

is

three

phase. The main

engines are

horizontal coupled-corn

pound,

and run

at

a slow

speed. 'l'hey

dri,e

the

generators

by cotton ropes. The

pressure of

the

generators, which

are

of the revolving field type, is from

500

to

550

volts per phase,

and the periodicity 40. Each

generator has

14 poles,

and gi ,

es

290 amperes

per phase

at 500 volts with a non-inducti,e load, each ha,'iog an

output of 250 kilo. volt-amperes, and there are three of

them.

Two

pits are

equipped,

and the c-urrent is

stepped

up to

2000 volts for ttansmission from the one to the

other.

Th r

ee-core cables

insulated with

vulcanised fibre

and

vulcanised bitumen.

The

main cables are

double

stee

l wire

armoured

. D

own

the Old C'oal

Seam shaft,

which is 220 yardH deep,

the cables each

weigh

2J tons

in the shaft. They arc fixed on twelve steel gtrders,

12in. x 6in.,

spaced

u.t 60fL.

centres, and

the cable

is

hung

in

a

double pitch pine cleat,

lift. )Qng by lOin. square

.. t

is

fastened to the j o i ~ ; t

by 1in.

diameter

bolts

passmg

thaough the wood,

and having

a ~ i n . wwught

iron plate

back and front.

Underground the cables

have been

laid

as

far

A.'

possible

in steel

semi-tube filled solid w.ith

bitumen

com pound in all swampy places. The t u ~ m g

runs

at the

Ride

of

and

below

the

rails

of

the

engrne

plane.

where risks

of

damage

from falls

or

wrecked

journeys

is remote.

Hubbish

i filled ovet

t ~ ~ tubes

throughout their length to an a,erage depth of lJm.

All

these

cables nre laid t h r o u ~ h intake roads. There are

several JOint boxes in the lines. all of the three-core

tO -

ELECTRICALLY DRIVEN

C E ~ T R I F U O A L

MININO

PUMP

11

20 -H. P. ELECTRIC MIN ING PUMP

Rwe \le

l

type.

The boxes

are

accommodat

ed

substan

tie.l bri k pits constructed in

cement,

with

cast

1ron coverll.

One p 1mp

is worked at

a

distance of

1900

yards from th

.e

shaft. There are thirteen moton;

at

Ty Tryst, thear

gears at thic; colliery, for both

pumping

and hauling

are

done there.

The whole installation is full

of

n t e r ~ s t .

There is IH

no means

agreemen

t

as to whether it is

better to use direct or polyphase cunent

io coal mines.

Th

ree-phase cunent

is

being

extensi vely

u ~ > e d

but

it

is

doubtful

if

it

will

ever entirely

displace dire

ct

current.

Fig. 8, page i,., shows a

pumping

plant electrically

equipped by the

Electric Construction

Company. The

motor is

o

the

three-phase type

of 36

brake

horse-power. I t

works

at

40 volts

and

5 periods

per

second. t is d i r e c ~

coupled through double

teduction

gearing to

a three

throw hoa-izontal pump, made by Messrs oseph Evans

and Co., of Wo herhampton.

There

is a bye-pass on the

rising

main which

allows

the motor

to

be

star

t

ed

up

aaainst o

light

lond. I t will be observed that the

b;d-plate is Hubdividecl to

enable

the

machine

to be

casil_y

got down

a

shaft.

and

that

the whole forms a well

designed and

trong

conRtruction. The

pump has

C\ tinders 1:lin. U\

9ir.

In Figs. 9, 10, i l

,

and 12, on this page, nre gi,en illustra

tions

of

a

series of p u m p ~

electricallyequipped by ?\le


6/16

Yl

THE ENGINEER

2-+

, 1904

l'ig.

l.i.

ht:"IO\\

-tLil tlw cllnrt>r. Thi illu .ttn.tion l'(')ln' tu: e, on

hich

prc-. . tht> Lru .hes. Jn the

cngrt\\

ing the sufllrllthall now ptocccize by m eans o ropes ,

and

the smaller sizes by

gearing . An example of

the

f

otmer

is

show

n in

Fig. 18, page ,ii.

T

hiign, the rope wheels being 6ft. 6in . diameter, and each

fitted with H all's type of friction clutch and automatic

brake, the

clutch and

brake

being operated by hand wheel

from t

he

driYing p

latfonn.

Th

e driYing pulle,\

is

8ft. in

diameter. grooYed for

nine

ropes 1{in. diamctet. Th i.,

F ie. 16-

DISTRIBUTINO BOAR

D, TY TRYST

COLLIERY

FC 17-

TRANS

FOR

MERS AN

D SWI

TCH

BOARDS,

BEDWELL

TY

COLLIERY

posed of r;oft annular

d i ~ c s

clamped in n co.'lt iron frame which electt;city

it>

most em ployed in T i r i t i ~ h coal mines. hauh\ge gear iRconstntcted

to

de liver about850 tons to the

und


7/16

u ~ E

b ~ e m:>unlecl with

douhle

-polC switch and double-pol . each 1

in,

ELE C'r l{

lf

1

AL SUPPLEMENT

di\'ision . The

heel

plate of thiq machine

is

made up or

rolled Joists, bolted

together

in such a way

that

they

can rea.dily be taken

apart

and

got

down a shaft.

The

motor in this particular instance is one of the firm' s

standard steel-clad opcnL.}

pc continuous-current I I I O t o r ~ > .

with a machine-cut pinion,

which

engages with a gear

wheel mounted on a cross-shaH, carrying on its

other

end a helical pinion. Th is, in its turn,

engages

wHh a

helical wheel, keyed

to the main

driving

sha

ft. On

this main shaft,

and capable

of being

connected

to it

by

friction alutcheK, are two

hauling

pulle

ys

for working

two

R e p a r t ~ t c road . Doth or these are 7ft. in

diameter.

They

arc

of

ca-;t iron,

and

the

dri\'ing

face in

each

Vll

a hancl he


8/16

...

V l

TH

N G I N R

-

r.

......

........

0

z

0

z

1 1

H

;:J

c.::

;r;J

z

.

. .

( l

E-xJ

......

....

.....;

p

z

. , ;

;;;

0

0

Q

;

re'

olu

ti

ons p

er minut

e. The

armature of the motor is of th e t t e d drum type, the

ri g .

23

>0U

B

LE

DAUM

IV

OTOR DRIVEN HAULAGE PLANT

c

hain machine. Through the

courtesy

of th

e mal1ers we

.n

e

enabled

to describe instances

of each of

th

ese

tJpe '.

The Hurd, or,

as its makers. :\Iessrs. l\Iavor and Coui

S

O:l,

ha ,

e

called it, the " Pickquick "

con.l

cu t

ter

, is sho

wn

m the

engraving Fig.

27,

page xi. We

de

sctib

ed

thi

s coal

cutter at some length in our issue of March 7th , 1902,

but in

order

to make

this

Supplement complete in itself

we may repeat a few particulars. .\ s will be seen from

the illus

tration,

the cu tt

er consists of

a bar-som

etimes

made taper

nnd sometimes parallel- in to which are fHted

the cutting

teeth. Ther

e is a spiral groo,c on the bar

Fi

g. 22 S INQLEDRUM ELECTRIC HA

UL

AGE PLANT

slots

being

lined with insu

lating channels

before the wind

ing

is

put

on. The

armature

coils are former wound.

The

m

et

coils

are

also

wound

on forme1 s,

and are

detachable from th e pole arms.

Figs. 23, 24, and 25, pages ix. and x., reptesent three haul

age

plants

whi

ch have been

electl'icall.v

equipped

by

the

Elect

r

ic

Construction

Company. Th

e first of

these

is a

double drum haulage fitted with screw-down friction

clutches

for

operating

the drums, these being worked by

band

wheel.

There is also

a foot brake gear.

The

motor

is of

th

e

open

four-pole type,

and it is

started up with a

cont

roller aimilar

to those

u

se

d

on tramcars. The

haulage

which se

rve s to

bring

out tbc pieces cut

away

. The bat

is

an-anged on a

head

which

is

capabl e

of suc

h mo\'e

ment that

the

bar can be turned in almost any direction,

and can cut upwardq or

downwards

or

at

any angle.

The

motot

driYing the cutter

is of

the four-pole com

pletely enclosed

typ

e,

with two shu nt

-wound

magnet

coils. The armature is of the

slotted

drum type. I f

alter

nating cunent is

used, then a motor of the three

phase

type

is

put

in.

The

motor is

then of the

squ

irrel

cage tJpe with slip

rings.

The

stator core,

with

the

con

ductors buried in

its

slots, is

contained

in a cylindrical

cas t steel shell with

ribs

cast upon it. The motor dr hes

du ::

tion

of

f

our continuous

recording ammttet

records

made

on four successive dass "-ith a n.edium-sized " Pick

quick" bar coa l cutter. These records were being made

at a time when we Yisited

the

colliery

where

the

machine

was

at

work, though, as a fact, actual cutting wns not

going on while we were there. We ha,e, however, been

supplied

with

copies

of

the records by l\Iessrs. :\IMor

and

Coulson. I t will Le seen that

in

the first record the

machine

was

cutting up

hill

with the gear

end leading.

In this

instance 120

yards

was cut

in 5t

hours,

including

stoppages.

The

se amounted in this case to well over

70 min. I f taken at 75 min.,

th i

s would represent an

actual cutting time of 4 hours-an n\'erage of 30 yards on

hour or 1 in. a

minute.

The

average

depth of cut

was

3ft. 9in.

The

average

\

'O

itage

at

the

switchboard

was

480, and the

amperes

cons

umed may

be read on the

diagram. The

other three

records, first, a cut of 120

ya

rds

in

5t

hours n c l u d i n ~

stoppages,

the machine cutting down

hill, haulage end leading; secondly, a cut of 120 yards in

5 t

hours including stoppages, cutting up hill, gea r end

leading; and thirdly, a cut of 120 yards

in

5t hours including

stoppages, the

machine

working

down

bill, haulage end

leading,

and

feeding by graYity alone.

An examination

of these diagrams sho

w

that

the

average current

being

used was about 15

amperes, though

the

machine was

frequentl,v working

in

full cut with 10 amperes. or even

unde

r.

Taking

the

average at

15

amperes,

however, this

represents an

expenditure of

energy

equal

to 480

X

15

=

7200

watts,

or, say, 9

65

horse-power. We

may a.dd

the following

details:

The

machine wa

s w

orking with

a

direct-current motor. The

bar

was tapered, anrl 4ft.

long. The machine

was

on rails. The inclination

was

1 in 5, the position of th e holeing

wa

s

at

the pavement

level, th e holeing

was

done

in

coal,

and

the nature

of

the

roof

was

" fakes."

Th

e

se

am

was

2ft. Sin. thick.

One

man

was

employed in driving,

two

in rail-laying, and one

in clearing

holeings.

The tonnage output per man

per

shift was

27t. The

driver was

getting 6s. 6d. per shift,

the rail-layers 6s., and the man cleating holeings 5s. 2d.

The

coc;t

of labour

per ton

wa

s,

as

a

total,

2

57

d.

The

machine

was

cutting at the rate of 37 square yards

per hour, or 150

square

yards per Hhift. The

electricity

consumed

per ton of coal produced was 26 unit s.

One

hundted

and ten tons

were

obtaine

d

in

th e shift,

and

25 per

cent.

of small coal

wa

s

produ

ced.

Th

e

duration

of

the

shift

at the face was Se\'


10/16

X

fift. 6in. re,.pecti'ely. An exatninat ion of

this

ma

chine, which is illustrat ed in Fig. 29, page xii.. will

show

that it

is compactly designed and

o;;trongly put

together. Tts

orking

parts are all enclosed, and its

ge'l.ring

runs

on ball bearings

and in

an oil bath.

The

o' cra\1 dimensions of the machine are fL 6in. long,

;Ht. :Jin. wide, and lft. 2in. high ftom the rail to the top

of the casing. The total height from

Hoor to

the Lop of

the m'l.chine

is,

with rails, 1ft. lO in., and

with

skids

lfL. 8in.

The

L':>tal weight is approxit tUl.tely 42 cwt.

T H N G I N R

s a r ~ The

armature shaft

is prolonged at both ends,

passing out or the enclosed case. in which the

armature

rnns through glands. One end of the shaft driYes the

disc through bevel gearing and a toothed wheel engaging

with

the

slotted teeth on

the

cutting wheel.

The other

end of the shaft works the feed gear, which is adjustable

in throw,

and

worl


11/16

T H E M A V 0 R A N D C 0 U L S 0 N .. P I C K Q U I C K ., C 0 A L C U T T E R

,

---

F J c y f

1 \ ~ well for this work. n i the firm's opinion

that there is undouhtedl.\

&

hwge field for polyphase machule R,

hut that whether in the long run t h e ~ will prove quite so satis

factory

as

the continuous current machines, e:o.-perience only

(1\Jl decide. It ill be interesting for

our

readers to compare

thi:> ' iew with that of :\I Holidav. of the Ackton H ll CollierY,

given in another column. li e, it will be seen, is o. strong

advocate of-three-phase

current

for mining work, and particu

lady

coal cutters. The motors fitted

to th

e machine ill

ust

rated

in Fig. 30 are designed to

ghe

their full horse-power con

tinuously without O\ crheating. With regard to repairs, the finn

has not fow1d that there is

a n ~ e a t

difference between the

cost of either system-di rect or a s e the

1111\

ehine ' in each case nrc equally suitabl.v designed.

Another form of electrically-worked conl cutter is that made

by Mather a.nd Pla.tt. It is shown in outline and elevation in

l ~

I' ........

.

..

:.,.

6 5

. ............ 120 Yds cut i n s;

ho

urs llfC/udm 9 slopp j8 S

14/ 4/ 0 4 .

Cu

tt

ing Do wnh l

fi

- Ha u la9 End Leading

feed ing by

Gr

a vot

_y

only

.....

~ ~ 1

r . : : ~

l

I

Fig.

28

AMMET ER RECORDS, THE " PIC KQUICK " COAL CUTTER

---

.

i

I

c

10

t H Se

bun-el

ty

pe,

and

with t

he starting

resistance

can be

quickly

removed and teplaced in case of need. The main gearing,

~ w i t c

nnd resistance 1\te all

pr

otected by a hinged cast iron co,er.

The gearing run,; in 8.11 oil bath.

Wi th this mt\Chine the makers claim, amongst

other

a.dvan-

1 tages, that the kerf or

und

e

rcut

" is absolutely cleared

I rom debris, l:lince

the

tools bring

out

a.ll the loose pieces into

I the

road;

that owing

to the

narrowness of

the

chain-currying

jib the coal can be wedged

or

spragged up within 2ft. of

th

e

sm face which is being cut, thus minimising the danger of the

jib getting bound by th e sett ling down of the coal ttfter it has

been cut; that the high speed of the working par t s gi

CS

the

tools sufficient

momentum to o\

ercome

temporary obstructio

ns.

such as lumps of

p y r i t e ~ .

without undul,v straining the

motor:

and that the ttex:ibility of the Jib counteracts the evil etl'ects of

uule,el rnils, and nids

th

e tools in springing out the

thb .is

in

I

ieces of considerable size

without cutting or

tenl'ing

adion,

thus enabling the tools to reto.in their edge foa a long time.

For a six-

foot.

undercut,

3.3

tools arc used

in

the cbttin. The'e

are

small, plnin, and of id

en

ticnl shape.

The machim

is de

, signed to work right or left-hnndcd on the long wall. The jib,

as

already mentioned. is made to

bWing

through nn angle ot

1

80

deg. This swinging motion is brought

about

bv means of

a detachable ratchet le,er, which works on to a biJtiarc-headed

spind

le actuating

n worm, which gears

into the teeth

of

the

I

worm-wheel

at

the back end of the jib. The Jib euts its w v

into the coo,l

n.t

t he start. n.nd does not, so we undcrstnnd, re

1 quire great ~ < p a c e to be holed by hand before beginning each

run down the f11ce.

This type of

toal cutte

r is probably

the

let\st used in

this

. . . . . . . cotantry. though

it

s in considerable faYour in Ute

t:

nitcd States,

the b r u ~ h e s

whach shut s down on

to

~ a c h i n e d aces, whach,j m 1ts

turn,

drives a four-thread steel worm workm

g_

on

to

n cut where, of course.

the

machine

mining of

coal is

much

mor-

t -4

m

q

1 0

1 0

t -4

txJ

txJ

z

M


12/16

Xll

THE N G I N R

-

possess some useful features.

\Ye conficlenLJ,v

anticipate too,

the wnlennay

hll.\e de,.,taucti\eOrdalllaging.cffectson able

want

of uniformity in this direction. \\ e haYe had

a

great

increas


13/16

..

lncity

a,, t.afe as anything

human can

be. The cable

111akert>

are by

no

tueanl bebindhand

in this,

as will be

amply

e-. ident b)

the '

arious

appliances

which are shown

in Figs. :33 to

42,

on this and pag e xi, . an d which are of th e

dc ..ign an

cl

manufacture

of

CaJiender's Cable and Con

"

tru

ct ion Co

mpan

y, L

imited.

One or the

lllO t

im por ta

nt

things to attend to is th e

I

.&..

l l

J...

[\

n

r

1Io1l-

";'r

"

~

))

ELE CT

RI

1

AL S U P P L E M E N T

vulcanised bitumen and double armoured. This cable, it

is claimed,

bei.J)g

lllecbanicall.' protected,

may

be fixed in

a shaft ' ' thoult any other cdvering, occupies

but

little

space, is practically fireproof, and may

very easily

be

manipulated

hen

~ ; u i t a b l e fittings

and

'

clam

p.. are

pro, ded. Home

of

the collier. engineer

prefer

rigid

fixings for th e cable being taken down ,hafts ; o

ther

s, on

r

I

' I

I

J,.

J

I

w ~

...

"

~ \

~

1 -o

t-: < ~

,

I

-

( ~ ~

'

71

a

\ \1$)/

r < .

1 -

' i

. - -

'

/ \ '- ./

/

~

/

"

T

..,,

7

...

~

-

l

\

'

\.

~ l

..--

1/

I

- .

/ .

,

.

I

- - - - - - a - -

,. ,

I

.

I

~

;jj(

I

A

-

\ ~ ) ~ 2 _

...

....,

t V\

'.;

/

\

rf

.

-

'

w.o.

tN

Se

.

Fi i '

.

32

- T

HE MATHER

AND

P L ~ T T COAL

CUTTER

m e

th

od

of

taking

the

m

ai

n cabl

es

down a shaft. In

another place

we

refer to the method in \ented by Mr. H oli

day,

of th

e Ackt

on

H all Colliery

Company.

mher

methods

are

to take th e

cables

down the shaft in oak or teak casing,

or

to c l

amp th em

in

se'

eral

ways

on

their way

do

wn the

r ~ s l e n e d lo 3tde

' ' ' '

of s h ~ f l

"

\ .

I ' :\.,

'.

"'

\

\ .

' ' ' t

.

' \' ,

r ~ s t e n e d to

s i

de

o s h ~ f t

\

\\

\ , ,

I

\

44:

-

(\) (\)

Tea q

or

06k

I

I

aml

()) : I ())

'

I

I

p l e cable

f or

3 phase

work

in

J .

32

-

:'


14/16

0

XIV

-

readily and

cheaply

done, there

IS no reas

on why such a

imple prccautton

-.hould not

be taken.

As

to

th

e

ca.blc1:1 in

the minel>

c w ~ ; e s , these

are all

too frequentlJ

ntn

"tthout any 'ery great regard to their

com

parath

fragile nature.

An ingenious

contri'

ance,

which

ib

shown

in i ~ . 3H, page xiii., has JUst been patented

by Me ..

sl t;.

C1lllendcr... Thit., t \s

shown, is

made so as to

be

lhed by dri'

ing into the

pit prop or othe

r

timbers in

a

naine, but.

in another

f

onu it

may be

attached by means

of conch

sc

rews.

H

will be

O bhaped

a , to render shocks

a

practical impossibility.

THE ACKTON HALL COLLIERY.

ONJo. of the tir

11t

C ~ > l l

c r i e s 10 this

country to adopt

electricity

tw o. wcan s of t r a n t ~ J l l i t t i n g power on a large

Fig . 43 - MOTOR DRIVING HAULAGE

GEAR

all y scct111ng the steel wire armouring-wheil cables

of th l

s

scale wo.1:1

the

Ackton

Hall Colliery

at

Feather

sto

ne, near

cha ra

cter are

used.

Th ese

anchor blocks are designed

Pontefract. We ha'

e recently been

permitted,

by the

with the object of eno;ur

ing

not

only

a good

mechanical

courtes.)' of :\fr. Hol'lyn H oliday, the manager, to

visit

grip,

but

also electrical cnntinuit,,

between th

e armourings

this collier),

and

we h:ne

been much

struck with

the

of the cables l

eading

to and from the box. All the intelligence

with which

e

lectricit

y

has

been

employed

interior

6 t t i n ~ s

of the boxes are

mounted

on ~ ; e p a there to assibt

in

carrying on

the

great variety

of work

porcelain insulators. The cables are

sealed inside

the met with. H ere we find

electricity employed

in almost

boxes

with

hox

compound, hich is

poured

in

hot

and every

possible direction, the

only exceptions being that it

.J

. 0

,

;

i

I

J

I

I

I

I

I

I

F ig 44 - VERTICAL

HAULAGE

PLANT- ACKTON

HALL

COLLIEI t Y

0

it

(_

-- -

THE E

NCI

NE ER

sets hard when cold. As will be seen, divis

ion

pi

eces

are

pr?vided,

w h i ~ h prevent the spr eading

where

1t

u1

not

requ1red.

Then

, too, m some instances, oil is

used in addition for

CO\

cring a ll the connections when

the

1.1e

hMc

been made. In

l \ I c ~ w n .

Callender

s' cliscon

is not

UBed fol' wi nuing or

large

fan dri

' ing. I t is

used,

1

howe\

er, for

lighting, hauling,

coal cutting, coal screening

and

~ h i n g pumping, for the driving

of

tools, &c.

At present the preponderance of :\Ir. H

oliday's

machincrv

is

direct current, but we are

by

no m e a n ~ certain t h ~ t

starting

r/r

uovo he would not equip his collien entirely

with

thrce-phnse

plant.

'

1

A

point

to

notice about the generating machinery nt

this

collier.) i

l:

that it

is

largely d1i' en by

s

te

am

t u r b i n e ~

an

d

tstco.m tmbines

worl


15/16

J v ~ 2- , 190-

ELECTR

I

CA

L

SUPPLEMENT

In addition

to

these

there are

the

following:-

ment consists of two 5ft. diameter

su

rging pulleys in

One

,

0

_k'lowo.tl \ 'olt.s. halves,

ea

ch fitted with

a

3ft

. diameter friction clutch,

.. belt- driven conlinuoua-cu

rr

eul

dyno.mo ... . . ... ... ...

110

Ttu

1

rned and bored nod bo

lt

ed

to

the

arms

of the pulleys.

Ono

:lO-

kil

owatt belt. driven ~ ~ n t i ;

u ~ ~ s - ~ ~

e ~ i . Jese are provided

with

renewable segments in the rim,

d y n a m ~ ... . .. ... ... ... .. . 110 and

are

brass bushed so

as to

run loose on

an

upright

l ne

10-k

lowo.tt drect-c:uupled t

ate

workshops, the wagon

shop,

and

the

coke

oven

hoist.

Th r

ee 10 horse-power

motors drive pumps. Three of 6 horse-power are

employed m the joiners' shops and

in

working pumps.

There are six of 4 horse-power engaged in like work

and in dri,ing the mechanics' shop, while there

are

five of

It horse-power each, which are at work in the lamp-room,

f

or

the lamp-cleaning machinery, for

dr

iving small fans,

and for working pumps.

Altogether,

there

are

some

ten th ree-phase motors

working in different places throughout the colliery. F

irst

of all there are fout of 20 horse-power fitted specially to

Hurd

coal cut

te rs made

by l\I

avor and

Coulsoo. To these

we shall refer in more detail later on. Th en there are

one

of 15 horse-power and fom of IO horse-power engaged in

pumping, and one, also of IO horse-power, working a

heading

machine

.

To

comp

l

ete

the electrical ec1uipment there

are thirty

fhe arc lamps a.nd about 1000

incandescent

lamps.

circular friction

segments

. These are

ac

tua ted

by

means

of levers connected to a sliding sleeve on

the

s

haft

, and

are worked by hand wheels, screws, c. The counter

gear

consists of a strong spur wheel

made

in halves

f'ixed

I

I

I

I

'

;o

l

I

I

I

'

' '

'

'

'

'

'

'

i

o

: .

;

XV

pulleys for duplicate driving.

When

first put down, th is

pl

ant

only

dro,

e one- haulage rope, this being some ruiJc

and a-half long. I t later on became ne cessary to add

another haulage rope of about

the

same length, and all

that

wa

s done was to add another

motor

and another

rope drum. On the occasion of our visit, this plant was

working most smoothly and .;uccessfull y.

The next most important haulages at thi s colliery arc

three dri,en by 60 horse-power motors. Perhaps th e

most int

erest

ing of

these

is

situated

.;o

me

1000

yards

row

the

pit

shaft,

and

is

em

ployed

in

hauling the

tub

s

up

an

incline 600 ya

rd

s long, a.nd htwing a

gradient

of 1 in 6

The

construction of this incline was rendered

nece

ssary

by

a.

fault being encountered which dxopped the seam

60

ya

rds.

I t

is interesting to note

that

two seams overlie

one another in this pit, the depth of earth between them

being exactly 60

ya

rds. The conseqence

ha

s been

that

the

uppex

sea

m has, at

the

fault, been found to comeexactly

at

the

level of th e lower seam,

an

d can be worked from

the

same level. The haulage plant working

th

e incline is

shown in Fig. 45, herewith.

The motor

, which is again of

th

e entirely open type, drives the haulage mechanism

through a

canvas

belt.

Th

e

gear

itself was co

nstructed

by Mr. Holiday, who used for

it

material

s which he had

at ha.nd, and we m ay, perhaps,

mention her

e that a point

which struck us at thi s colliery was the way in which

material at hand had b

een made

use of. Special

machin

e

ry

f

or

special work is by no m

ea

ns

the order

of

the day , but rather the application of machinet-y already

on the site in any direction which

it

might

be

required.

Both Figs.

43

and

45

show well the conditions

under

which

electrical machinery

may

be expected to work under

ground. Indeed, the conditions in both cases may be

said

to

be above

the

a\erage, f

or water

is very

nearly

absent, and is, at a ll events, present in very small

quantities, thus forming a complete contrast with many

anot

her

mine.

In

the

back of the engraving, Fig. 45, will be seen a.

small countershaft secured to

the

rock roof of the

machinery chamber.

This

works a small

ram

pump.

I t will be unnecessary

to

go much

further

into detail

with regard to the various haulage plants at this colliery.

We may, however, draw

attention to

Fig. 46, below,

which 'bows a

plant

wherein the

motor

is coupled direct

to

the

gear

an

d not through a belt as in

the

other

instances. This g

ear

was

constructed

by l\Iessrs. Qua.lter,

Hall

and

Co

. I t is carried on a steel girder frame, and

can

be

moYcd from place to place ns required . I t con

sists of two hauling dt-ums in halves, 4ft. diameter, bushed

with brass, and working on

A.

main shaft driven by means

of jaw clutches. A

spur

wheel

in

halves is also keyed

on the shaft, and geaxs with a pinion

on

the counter

shaft,

on

which is a.lso keyed a. machine-cut

spur

wheel

gearing into a raw bide pinion on the motor spindle.

The

motor

is of

25

horse-power.

Th

e whole of

the

brake

/

PI

an

.

;

I

'

I

'

'

'

'

I

'

'

I

'

I

'

I

I

'

i - -

.J r ..,

, - -_ I / .

/ 1

, . I ~ : /

.

::.. .. o::..

.

;

To

giYe

merely this list of electrical appliances

and

their app

li

cations affords but a faint

idea

of

the

ingenuity

with which

they

have been employed. Taking the

haulage

at

Ackton H a

ll

Colliery first, we find

that there

are f

our

separate installations. The

largest

of

these

is

situated close to the bottom of one of

the

shafts .

We

illustrate

it

in Figs. 4.3 and 44, page xiY. I t is interesting

in more ways than one .

In

the first place, the motors

are not mounted at ground level,

but

are erected

on

a

pla

tf

orm

carried

on

hcav_y

timbers,

the

platform being

?uilt in a recess

hewn out

of the solid rock roof, and being

Ne

ll up out of

the way

of tmythir1g passing in the road

unde rneath . 'l here arc two direct-current motors, of

the

type

shown in Fig. 4 : ~ . They are

entire

ly open,

as th is part of the colliery

is

ne' er likely to have

gas in it. We noticed

that

b r u s h e made up of

thin brass strips

were employed,

and

we were in

formed by Mr. Holiday

that

each motor

man

throughout

the min e made

his

own bt-u shes. Th e motors drive by

link belting

on

to two pulleys connected with the gearing

of the haulage mechanism. This, as will be seen in

Fig. 44, is of the vertical type. Jt was constructed by

Qualter, H all

and

Co., of Barnsley. Thi s

~ r r a n g e -

" T

HE

ENG INEER ,.

Elevat ion

.

. . -- i _.__ /

'

......: ~ , ~ ; . - ;...--

/ '

-----

SwAI N Se

F ig. 46 - MOTOR DRIVEN HAULAGE PLANT

ACKTO

N HA

LL

COLLIERY

on

an

upright

shaft.

Thi

s gears into a pinion working

on

a.

counter

shaft ,

on

which is also keyed a bevel wheel

made

in halves, gearing

wi

th two pinions \\Orking

on

separate cou

nte

r shafts on which

arc

k e ~ ed strong belt

and clutch levers are brought

to

a position near to

gether, so that the whole is under control of

one

man.

The screens

are

driYen by an electric

motor

by means of

l\ belt; the plant does

not

' call for nny ~ ; p e c i a l mention.


16/16

XV l

being

dealt with

in the

same

way

as

an,v

other

above

ground installation.

The same remark

applies

to the

coal

washing machinery, which is driven by

two

80 horse-power

motors.

In both instances

the work is well

and

easily

done.

Regarding

the

various

other

applications of di rcct

cunent motors

to

work of different ltinds, it is

perhaps

unnecessary

to

speak.

I t may,

however,

be

of

interest

to

repeat

that

they are

employed for working a disintegrator ;

a saw

mill; machinery

in a brickyard belonging

to the

colliery;

chatT

cutting in the stables; machinery in the

estate

workshops

and quarry;

in the wagon, joiners',

and

mechanics' shops, in the

latter

of which some of the

motors are coupled singly to larger sized

machines;

th e

.. _______

-

-

~ ~ ~ ~

T H N G I N R

wheel loose

on its

shaft,

and

close to it a disc which

was firmly fixed

to the

shaft. Oo the

rim

of

th i

s

disc was a projecting lug, and on the side of the bevel

wheel was

anot

h

er

projection,

w b i ~ h

just

c l e a r ~ d ~ h e

rim

of the disc, but engaged w1th

the

proJe.ctJOn

upon it. Thus, the bevel wheel could

make

practiCally

one

revolution

without

driving

the cutter

wheel shaft,

and

hence

without

doing

any

work.

Th

e motors were geared

5

to

1, so that

they

could make live revolutions free. A

v

er

sing switch

was

also added,

and with

thi s an11.ngemen.t It

was found possible

to hberate

the cutter

wheel, by

lettmg

the

motors

run

forward, giving a jerk

to

it. This combina

tion worked so well that

the

resistance rings were done

away

with,

and the

mo

.

started

by being connected

~ ~

-

-

----

--

----

r lg 47 - CO

AL

CUTTER AND T HREE PHASE MOT

OR

c o ~ < e

o,-e::I

hoist; lamp

cleaniug

machinery;

tar.s

and

pump

s. We muRt not forget

to

mention a point in con

nection with the coal washen1.

I t

is necessary

to

run

these

machines for considerable periods at

about

quader

speed to prevent the sl udge from se ttling solid in the

tanks.

Mr.

Holiday obtains

this

slow speed by

the use

of two

motor

s, and by

means

of a

switc

h which

can

couple

the

two motor in

series

and the

fields in parallel.

'Ve

mentioned

earlier oa

that

three-pha

se motors were

usE:d

for working the coal cutters. .Mr.

Holida

y, who

believes s

trong

ly in

the use

of

three-phase current

in coal

cutting,

was

the

first, in

this country

at all

event

s,

to

apply successfully this

method

of driving

to

coal-cutting

machinery,

and

we

are

enabled by h is co1rtesy

to

give in

Fig.

47 , above, a

reproduction

from a

photograph

of a

H

urd

coal

cutter, made

by

.Mes

srs.

Mavor and

Coulson,

and adapted

for

three-phase

working by Mr. H oliday him

se

lf.

In

a

communication

which

he made

some

little while

ago to

the Journal

of the British Society of Mining

Students, he

gives

some

reason for adopting

three-phase

cutTent for coal

cutters, and

details

some

of

the

experi

ences be met

with before

attaining

success.

In

com

mencing

the

subject

he draws attention

to

the

fact that,

with continuous

coal

cutters,

the

motors

used

are

usually

of

the

series type. In these, he explains, insulation is

difficult because of

the

limited space,

and maintenance

is

not easy because of the seve

re

vibrations

to

which the

motor

s

are

subjec

ted,

this vibration

being

one

of

the most

frequent causes

of breakdown.

Rubbing

contacts

are

also

necessary

with a consequent liability

to

sparking,

th is being

due perhaps to

mechanical,

perhaps to

electrical causes. He

mentions

the

f a ~ t

that

maker

s do

their utmost to

minimise

the

dangers

consequent on

this.

The

y design the

motors

in the first

instance

so that

they

give a

minimum

of sparking

and

then enclose them com

pletely in cases which

are

call

ed

"gas

tight." Inspection

covers

must,

however, be pro\'ided, he con tinues, "and,

as they must be left so

that

the men in the pit can

open

them

,

they are

a

bout as

reliable as an unlocked s

afety

lamp in

the hands of

miner

s

."

In s

tarting

a series motor,

he

goes on,

if

the full cur

rent

is

switched on su ddenly

while the

motor

is

at

rest,

a

heavy rush

of cun-ent passes

through the armature,

which

lasts

until the f

uses

blow or until it is switched off

again.

I f

this

rush

of

current lasts

long,

the armature

is

burnt. Starting

difficulties

are

overcome

by means

of

re

sistances,

but

these

are

a

constant

source of trouble.

Owina to varying

t e m p e r a t u r e ~

and t0

th

e vibration,

s c r e w ~ are

liable

to

work loose

and arcing

to

be se

t up .

On

the other

hand, with continuous

current

only two

cables are necessaty.

Two-phase currents be passes over, saying

that

there

are

difficulties

in

starting.

With

three-phase

currents

three

cables

are

required.

Th

e motors start fairly well.

In

these

the full working cmTent passes through the

stationary

part

of

the

motor

s

only;

con

seq uently

there

is more room

for

insulation, and breakdowns are much

less

frequent than

with

direct-current mot?t'S,

T ~ c

gre

at

disadvantage of the three-phase wotor IS

thn.t

1t

has a

very small s

tarting

torque-not nearly

as great

that

in

a series

continuous-current

motot.

In order to

rncrease

this starting torque resistances are introduced into the

rotor circuit, and

as

a consequence

there

must be

three

slip

rings to convey the

cutTent from

th

e

rotor to the

resistances

. Th

ese

rings

are

of

so

lid brass,

and they are

not liable to spark from electrical causes, but f lay d so

if subjected

to vibration.

.

The

se were th e

c o n s i ~ e r a t 1 0 n s

which

confronted

Mr. H oliday

when he

first

se

t btmself to

work

out

the question

of electrical coal cu tin{:? H e deci.ded

finally that if the three-

phase motor

could

be gt 'e

n

u ~ C l e n

t

starting torque,

it would

be far

s

afer and l c ~ s m p l i c a t e ~

than the cootinuous-cutTent

motor. In his

first

expen

ments

he

used a.

Diamond

Coal Cutter Company's cu

tter

wheel and

two

10 hor

se-power

Brown Bo

veri motors.

H e, after some experiment,

made

the driving bevel

directly to

the

mains.

Thi

s Mr.

Holiday

considers

to

e

practic

ally

the secret

of

the

application of three-phase

motors

to

coal cutting. H e

has

since adopted Hurd bat

cutters,

and has

fitted each with a 20 horse-power three

phase motor.

He

has never had

a

u

se blow with a

three-phase motor,

thou

gh several

times

he

has

bad disc

machine

s pulled up dead.

Th

e

rea

s

on

for

this

is, as

he

explains, that the motors

and the

mains have a high in

du

ction which checks

the

flow

of

current. H ence

be iE

able

to

place all

his

fus

es

on the surface-a

great

point.

Mr. Holiday considers that the man,y advantages of three

phase

plant quite counterbalance the extra

cost

in cable.

He

has

found these motors work well,

and has never

had

to change the

bearings. He fits

the

motors to

the cutters.

and

makes

his

own

switch-boxes

at

the

colliery. Indeed.

th is remark applies

not

only

to

coal cutters,

but through

out

th

e whole electric

system

.

The

coal cutter switches

are

closed with an accurately machined ' cover and

cement

Fig

48 C

ABI:.E SUSPENDERS

joint.

The handle

works into the box through a gland.

H e

has never

hA.d an.v sparking.

Th

e voltage used is 320.

'Ye noticed

at

this

mine

an ingenious contrivanc:?,

for suspending

the

cables going down

t ~ e

shaft, which

has been patented

by Mr.

Holiday .Mr. Holiday

prefers to

use

single cables

fot this

purpose,

and

to

have

them

of

bard-drawn copper, with a

light

insulating covering.

At

the top

of

the shaft each

cable is gripped in

the clamp,

and

is held

there by means

of the six

bolt

s a.nd

nuts

.

Thorough insulation is

ensured

by

the

construction of the

suspender, which consists of an inverted cast iron basin

provided with a

banger

and

with

a central tube, up

through which

the

stalk of the cable grip is pas ied. 'l'he

bottom

of the annular space formed in the cast iron basin

by

central tube

is filled

in with

a ring of wooc1. Over

thi

s

is pl

aced

a ring of rubber,

and the remainder

of

the

space

is filled

up

with oil. The gripper

stalk

is passed through

a hole

in

an inverted

thimble, and

secured by a cotter.

The

thimble

is

then

dropped

into

the oil,

and rests

on the

rubb

er.

The

whole is

then

closed in

with

a

dom

ed

covering. Mr.

Holida

y informs

us

that

he and others

have

found

this arrange

m

en

t an lwer admirably.

The

two

engraving

s Fig

s. 48 and 49,

on this

page-show thiB

ap

p

aratus

in

sec

tion,

and

as

it is

an-anged in

actual

practice. , In

th i

s cMe the three cables we1e each

600

yards

long.

'l

be engraving i ~ : ~ reproduced from a

photograph taken at the

Ackton H all Colliery.

The

sus

pe

nders

are so ananged

that

the cab les

hang

well

cleat of

the

side of

the shaft, and

when

they reach the

J 24, 1904

bottom

they are

given a sligb bight before being looped

up

to

the

insulators, so that

any moisture

which

may

collect on

and run

down

them

will drip off at

the bottom

of the bight or loop,

and not reach the insu lator

s.

We

ca

nnot

leave

this

mine without

making

mention

of

a th ree-phase

pumping plant

which

has been

installed.

A reservoir

has

been constructed in a field belonging to

the Colliery Company

some

1000

yards away

from the

shafts. The

water

from a st ream

some

500

or

600

yards

away is pumped into

this

reservoir by

means

of a centri

fugal

pump

dri,en by two 10 horse-power motors coupled

direct on

to

the

shaft

on

either

side of the

pump. These

motors

have

also

been

depri,ed of

their

slip rings,

as

have

the

coal

cutter

motors,

and

a

re starte

d by being

connected

direct

to

the

mains.

An

ingenious inductional contrivance,

invented by Mr. Holiday, shows when the

water

level

is

g e t t i o ~ too

low, so that t ~ e

a.ttenda?t may know when

to

switc

h off the

current

w1thout ha.vmg to walk

the 5(0

or

600

yards to

see.

Th

e water from the reservoir is

pumped

to the

pit

m o u t ~

by means

of a set of

l e c t ~ i c l l ~

driven three-throw

honzontal pump

s, the

motor

m th1s

case being of 15 o ~ s e p o w e r

three-pha

se. ?'his is st at;ted

by the aid of res1stances, t ~ e r e n o ~ ~ m g suffic1ent

'give" in the sys tem to perm1t of

their

bemg done awav

with.

Its ordinary

working

current with

a voltage of 320

e

E

GI HC E

.

-

r

I

I

Fg.

49

- T HE HOLID

AY

CABLE SUSPEN DER

=s about 44 amperes. I f the

currer.t

is

switc

hed

right

on

without the resista.nces, the motor simply hums

without

moving,

and

a

current

of

about

100

amperes

passes.

THE

BOL

[

OVER COLL

I

ERY.

Another

colli

ery

which we were enabled, by

the

u r t e s y

of

its

manager,

1\Ir.

Houfton,

to

visit

was that

belonging

to the

Bolsover Colliery Company.

Thi

s

pit ill

interesting in that, having

some

time ago adopted

di rect

unent

working for

its haulage plant

s, it has

recently

installed a fairly large

three-pha

se

plant. The

direct

cunent

plant at

bank consists of a lOO-kilowatt compound

wound four-pole dynamo, giving 600 volts

at

720 revolu

tions p

er minute

this

being belt-driven by a

~ i n g l e c y c c r

horizontal engine

made

by Messrs.

Jobn

Davis

and

Son, of

Derby,

and

a two-pole Goulden

dynamo,

giving 67

amperes

and

volts

at

630

re ,

olutions. It is dt;ven by a single

cy linder horizontal engine by

means

of an overhead

countershaft

an

d belting.

There

are, in addition, two

lighting plants; one of

these

gi\'es

200 amperes

1 t

110 volts

and

940 revolutions per minute,

and

the

otl::

e :

180 amperes

at

110 volts at 805 revolutions per minute.

Both

of th ese

are

driven by horizontal

ltobey e n g i n e ~ : ~

The firs

t-named

generating plant drives a m

otor

which

is

an

exact

counterpart

of

the

dynamo

as regards

size,

and

this

actuates

a haul

age gear

by

means

of a belt.

The

second

pl

an t, until the inst allation of the three-phase

dynamo, drove

a series-wound

motor near the

bottom

of

the shaft,

but

at pre

se

nt this is

not at

worl< though we

understand

it is s

hortly

to be re-employed.

The thre

e-

phase t a l l a . t i o n consists

of a

8 0 k i l o w a t ~

We

stinghouse

generator running at

514 revolutions, anJ

with

a voltage of 440.

It

is driven b y a

vertical

We

sting

house engine with

two

cylinders,

each

20in.

by

16in.

stroke. The

motor

dQwn the pit is of the W e s t i n g h o u s : ~

make and

of 200 horse-power,

and

works

at

580

r e v o l u t i o n ~

per

minute,

with a voltage of 400. I t drives three

endless

rope

ba.ulages of 440 ,Yards, 3600 y a . r d s ~ : ~ h o r t

to be m

ade

4300

yards

nd

2000 yard

1904 electric mine

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