5-4. MAIN PROPULSION ENGINE/MARINE GEAR - REMOVAL AND RUN-IN
MAINTENANCE INSTRUCTIONS. (Continued).
RUN IN (Cont)
(a) The function of the dynamometer is to absorb and measure the engine output. Its basic components
are a frame, engine mounts, the absorption unit, a heat exchanger, and a torque loading 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 volume 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 horsepower 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
(a) Certain instrumentation is necessary so that data required / to complete the Engine Test Report may
be obtained. The following list contains both the minimum amount of instruments and the proper location of the
fittings on the engine so that the readings represent a true evaluation of engine conditions.
1 Oil pressure gage installed in one of the engine main