Cooling Requirements - AW 200 Operator's Manual

SECTION
3
COOLING REQUIREMENTS
The most important part or requirement is water
for cooling
the dynamometer. Through the
conversion of mechanical energy into heat energy by the dynamometer tremendous amounts
of
heat
is
created.
The unit of quantity of
this thermal energy is ealled
British
Thermal Units or B,T.U.s.
One
B'T.U.
is the amount of heat (thermal energy required to raise the temperature
of
1
pound
of
water),
10F
in
1
minutb of time.
778 isthe number of foot pounds of meehanical energy equivalent
to
1
B.T.U.
and
is called
the
mechanical energy. It
takes 33,000
ft
lbs of
work in
1
minute to produce
t
horsepower.,
33,000 divided by
778:42.6
B.T.U, per horsepower.
Let's
say
we. are
testing a
100
H.p. tractor on
a
dynamometer.
100
H'P. X
42'6:
4260
B.T.U. per minute of eooling.
If
we
are
to load test
t
hour we have
a
totalquantityofheat of
4260
B,TU. @minuteX60:255,600B.T.u.perhour. Thisisequaito
a
furnace roughly heating
2
Yzhouses
with
the thennostat eompletely
u.?
on
high for
one
hour.
trt
is this heat whish must be removed from the dynamometer in order
io
keep
it coal. Without
proper cooling your test periods would be short
and
the dynamometer
life
will
have short
intervals befwoen major overhauls. Installations
with
an
insufficient
supply of water must
follow
Inspection/Servicing Brake Drum Unit in Section
6
very closely to prevenidamage to
the
equipment or injury
to personnel.
The
following
charl shows several types of cooling systems that have been used down throush
the years.