Gorman-Rupp Pumps 84A3-B 818301 and up - Manual (Page 14)

80 SERIES OM−00923
PAGE B − 7 INSTALLATION
the smallest sheave diameter is 8 inches, the pump
speed is 1250 RPM, and the belts are uncogged
Yy-T type, then 11.5 lbs. of force on the tensioner
should show 1/2-inch (12,7 mm) of deflection.
A tension tester is available as an option from Gor-
man-Rupp (P/N 29513−001). Other tension test-
ers are available from your local belt/sheave dis-
tributor, and work on a similar principal.
To use the Gorman-Rupp tensioner, measure the
belt span as shown in Figure 4. Position the bottom
of the large O-ring on the span scale of the tension-
er at the measured belt span. Set the small O-ring
on the deflection force scale to zero.
Place the tension tester squarely on the belt at the
center of the belt span. Apply force on the plunger,
perpendicular to the belt span, until the bottom of
the large O-ring is even with the top of the next belt,
or with the bottom of a straight edge laid across the
sheaves.
Read the force applied from the bottom of the small
O-ring on the deflection force scale. Compare this
force with the value shown in Table 1 or 2 and ad-
just the tension accordingly. Note that the tension
for new belts is higher than that for used belts to
allow for expected belt stretching. Do not over-ten-
sion used belts to the higher deflection forces
shown for new belts.