Gearboxes are used in virtually all industrial plants,
machine shops, large and small manufacturing facilities, as well s in your own car or
truck. Excess heat in a gearbox means friction - and friction means wear and inefficient
energy use. This demonstration was designed to look at the cooling and lubricating
efficiency of AMSOIL 75W-90 Gear Lube.
The demonstration used two identical gearboxes that were
linked to two 3/4 HP electric motors running at a constant voltage. The gearboxes were
enclosed in cases (to stabilize ambient air temperature) and drove two fluid transfer
pumps which circulated a heavy-weight motor oil drawn form a common reservoir. This
motor oil increased the drag on the pumps and gearboxes causing higher temperatures and
loads for all mechanical parts.
Each test ran for 3 1/2 hours. Gearbox A started out
with petroleum lube; Gearbox B started out with AMSOIL 75W-90 Gear Lube. At the
completion of the 3 1/2 hours, Gearbox A was changed over to AMSOIL, Gearbox B to petroleum,
and each ran for another 3 1/2 hours.
To monitor the test, temperature probes were placed in
various locations around the gearbox and motor, including inside the gearbox, bearings and
gear lube, and on the electric motor. Temperature readings were taken every five minutes,
and the temperature curves were reasonably stable by test's end, varying less than 3°F
after the first hour of any test.
The graphs below plot the results from the demonstration,
with Gearbox A bearing, fluid (gear lube), and motor temperatures on the top, and
Gearbox B's results directly below.
The heat-reduction of AMSOIL Gear Lube (in yellow)
is consistent and conclusive. In all cases, the test temperatures for AMSOIL-lubricated
gearboxes were lower than its petroleum counterpart. with bearing temperatures reduced
by 1°-34°F, gearlube temperatures by 10°-18°F, and motor temperatures
Likewise, average temperatures after the initial 1 1/2
hours of stabilizing were much cooler for gearboxes equipped with AMSOIL (see chart
The demonstration shows AMSOIL Gear Lubes can significantly
recuce heat and provide better energy and maintenance savings.
Gearbox bearing temperatures were reduced by as
much as 34°F, or 19% cooler than the petroleum-lubricated bearings. Since the
bearings generally take the greatest amount of wear in these units, this is quite
significant. Reduced heat means reduced friction, and that means less wear and more
efficient energy use.
Gearbox fluid temperature is a good "overall"
indicator of what is taking place inside the gearbox housing. AMSOIL Gear Lube ran
25°F cooler in Gearbox A and 8°F cooler in Gearbox B than petroleum, for a
14% and 5% reduction in temperature respectively.
Motor temperature is a good measure of how hard
the engine must work to drive the gearbox. The harder the engine has to work, the
higher the temperature will be. AMSOIL Gear Lube reduced motor heat by 4°-10°F,
or 3.7%. Although it's not possible to make a direct numerical correlation to energy
saved, it can be generally stated that these findings point to significant energy