Section 7, Belt Drive; Figure 7-1 Belt Tension 3Vx Belts - Gardner Denver EBB BB-7.5 HP Operating And Service Manual

SECTION 7
BELT DRIVE
Proper drive belt tension and alignment are provided at
the factory, however, good practice dictates checking
the drive alignment and tension after shipment and be-
fore initial start–up.
Sheaves should align straight across the front with a
straight edge. The best tension is just enough tension
to keep belts from "squealing" on start–up.
Excessive belt tension can damage
the equipment. Tension the belts as
shown in FIGURE 7–1.
Belts can be changed when necessary by the following
instructions. First, disconnect, tag and lockout power
to the starter. Then remove the wire guard. Then loos-
en, but do not remove, the four motor foot nuts.
Next, use the adjusting screws in the motor base to
loosen belt tension. Remove the belts, and replace with
new belts. Check for correct belt tension and re–attach
the wire guard.
Motor
H.P.
7.5
10
15
CHECKING BELT TENSION – Using a spring scale,
apply a perpendicular force to each belt at the midpoint
of the span and measure the deflection. Correct deflec-
tion force and deflection are shown in FIGURE 7–1. To
tighten belts, merely increase the center distance.
No. Deflection
Of Force Pounds
Belts (per belt)
3
3
3
FIGURE 7–1 – BELT TENSION 3VX BELTS
13–8–612 Page 31
Interference between the fan and the
orifice can damage equipment. Be
certain the orifice has even clearance
around the fan before starting the
unit.
When a new set of belts is installed on
a drive, the initial deflection force
should be 1/3 greater than shown in
FIGURE 7–1. Recheck tension fre-
quently during the first 24 hours of
operation.
6 – 8.5
6 – 7
6 – 7
Deflection
In
Inches
5/16
5/16
5/16