ChipBLASTER Inc
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18.0. BELT INSTALLATION (Cont.):
18.3.1.2. Increase the belt tension until the belt feels snug or taut. Avoid over
tensioning the belt.
18.3.1.3. Start the drive and apply the most severe load condition. This may be
either the motor starting torque or during the work cycle. A belt that is
too loose will “jump teeth" under the most severe load condition. When
this occurs, gradually increase the belt tension until satisfactory
operation is achieved.
18.4. Belt Tensioning - Force Deflection Method:
18.4.1. An alternate numerical method can also be used to properly tension the belt on a
Synchronous drive. This procedure, commonly referred to as the Force Deflection
Method, consists of measuring the pounds of force required to deflect the belt a
given amount.
18.4.1.1. Install the belt as per Steps 1 and 2 of the General Method. Measure the
span length (in inches) as
illustrated in Figure 11.
18.4.1.2. From Figure 11, determine the deflection height required for the drive.
The deflection height is always 1/64" per inch of span length. For
example, a 32" span length requires a deflection of 32/64" or 1/2". To
measure the deflection height place a straightedge from sprocket to
sprocket on top of the belt or wrap a string or steel tape around the
sprockets on top of the belt. This will serve as a reference line to
measure deflection inches.
18.4.1.3. Using the formula at below, calculate the minimum and maximum force
values (lbs.).
18.4.1.4. Using a spring scale, apply a perpendicular force to the belt at the mid-
point of the span as illustrated in Figure 1. NOTE: For belts wider than 2
inches, it is suggested that a rigid piece of key stock or something
similar be placed across the belt between the point of force and the belt
to prevent belt distortion. Compare this defection force value to that
found in 18.4.1.4. Adjust belt tension accordingly.
Actual belt installation tension required depends on peak loads, system
rigidity, teeth in mesh. etc. In some instances it may be necessary to
gradually increase the belt tension to achieve proper operation of the drive.
18.0