5-33. ENGINE ASSEMBLY-REMOVAL AND RUN IN-MAINTENANCE INSTRUCTIONS (Continued)
ENGINE RUN-IN INSTRUCTIONS (Cont)
(a) The function of the dynamometer is to absorb
and measure the engine output. Its basic com-
ponents are a frame, engine mounts, the absorp-
tion unit, a heat exchanger, and a torque load-
ing and measuring device.
(b) The engine is connected through a universal
coupling to the absorption unit. The load on
the engine may be varied from zero to maximum
by decreasing or increasing the resistance in
the unit. The amount of power absorbed in a
water brake type dynamometer, as an example,
is governed by the volume of fluid within the
working system. The fluid offers resistance
to a rotating motion. By controlling the vol-
ume of water in the absorption unit, the load
may be increased or decreased as required.
(c) The power absorbed is generally measured in
torque (lb-ft) on a suitable scale. This
value for a given engine speed will show
the brake horsepower developed in the engine
by the following formula:
BHP = (T x RPM)/5250
BHP = brake horsepower
T = torque in lb-ft
RPM = revolutions per minute
(d) Some dynamometers indicate direct brake horse-
power readings. Therefore, the use of the
formula is not required when using these units.
(e) During the actual operation, all data taken
should be recorded immediately on an Engine
Test Report (see sample) on page 5-522'