The Marion daily mirror. (Marion, Ohio) 1892-1912, 1909-12-18

billS case ONLY Slntl pOTuou vi
the power plant need be in operation
or connection may be had with a
local power Co, on an arrangement
for them TO furnish power in small
quantities, in such emergencies.
In installing new, or considering
extention addition to an old plant,
all conditions should be carfully II
analized so that the system selected
shall be best adapted to the nature
of the work and general lay out OF
the plant.
The matter of speed variation is OF
utmost importance in deciding /
whether to use A. G. or ID. c. or
both.
II very little varlble speed is re-
quired, polyphase A. c. would be ma
tural choice owing to the many ad-
vantages of the inductions over the |
direct current motor, chief of which |
Is the abseme of commutator and
brushes Uhe cause of the largest
portion of d. q. motor trouble) and
rhe simplicity and economy and
maintainance.
Where the speed requirements are
the reverse, ID. c. should be used be-
cause of its superior adaptibility to
variable or adjustible speed motors
There is in many cases between
these TWO extremes where a COM
pos'te plant should be adopted. Reli-
ability aud economy and increased
production being weighed against
the amount of difference in invest
ment. In some cases fire risk would
be an important factor especially in
dusty places or in the presence Of
combustible gases.
This paper being intended to treat
of the application OF motors ito ma
chine tool drive and as very large
percentage of mchine tools require
versible or adjustable speed, my
further remarks will be con1ned to
the ID =. motor as used in the plant
of the Marion Steam Shovel Co
where | am employed. And will take
departments separately and describe
the requirements of the various ma
chimes and the actions and character
istics of the motors driving them.
In the foundry the principle mo-
tor duty is in the operating Of
travelling cranes. This work requir-
ling frequent starting and stopping
various speed and loads and high
starting torgue. Serious motors are
used exclusively.
A three motor crane being equip
ped with a travelling trolley and
joint motors. The travelling motor
driving the crane longitudianly over
the area and the trolley latedally
and the hoist raising and lowering
the load. This motor is equipped with
magnst OF which Is connected In
series with the motor, the brake be-
ing released when the motor is run
ming and not when the current Is cut
off. The duty of this brake is to
slacken the speed Of the armature
which on lowering acts mechanical
broke located on an intermediate
shaft between the armature and
winding drum.
other foundry mo,or equipped ma
chimes are charging machines which
ace about the same nature as cranes
and using the same motor equip
ments. and grinders and blowers
The sand grinders on ad'ount OF the
varying load and nearly constant
speed should be equipped with COM
mound motors and the blowers shunt
motors.
OF course this apples only in an
exclusively d. c. plant as the suirrei
Gag induction motor would be tine
ideal drive for this class OF work
and in any fnuture reference TO ID.
c. motors in constant work it Is to
be understood that they are consid-
cred only where A. G. is not avail
able.
The chipping and cleaning depart
ment tools are saws, emery
wheels ehapers, rattlers and sand
blast. The saw shaper moters should
he of the interrels shunt adjustable
type. Ra'tlers and sand blast COM
mound There As also in this depart
ment and are welder outfit, current
for which is derived fom a 60 Won
generator driven by a 500 volt di-
rect connected motor. This being US
ed for patching and repairing steel
castings.
I'm the boiler and structural shop
all types OF motors are required
drill press motors should be on
lcompound type, punches, and shears
compound and the machines equip
lped with a heavy fly-whell, which
should lie so designed that Ut vii
store away enough energy shear ol
punch the material and in so doint
TO slacken the speed of motors ONLY
enough % allow full load current u
In the machine shop the adjust
able speed motor predominaues
These should all be of the interplo
shunt type, Speed being controied D.
varying the strength of the shun'
la,s L. oAodanov pf tha motor be