Comfort-Aire HBH Series 6-10 Tons - Manual (Page 29)

Heat Controller, Inc. HBH SERIES IOM Manual
28
General rules of tensioning
1. Ideal tension is the lowest tension at which the belt will not slip under
peak load conditions.
2. Check tension frequently during the first 24-48 hours of operation.
3. Over tensioning shortens belt and bearing life.
4. Keep belts free from foreign material which may cause slip.
5. Make V-drive inspection on periodic basis. Tension when slipping.
Never apply belt dressing as this willl damage the belt and cause
early failure.
Tension Measurement Procedure
1. Measure the belt span (see sketch).
2. Position bottom of the large “O” ring on the span scale at the measured belt span.
3. Set the small “O” ring on the deflection force scale to zero.
4. Place the tension checker squarely on one belt at the center of the belt span. Apply a force on the
plunger and 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.
5. Remove the tension checker and read the forct applied from the bottom of the small “O” ring on
the deflection force scale.
6. Compare the force you have applied with the values given in the table below. The force should be
between the minimum and maximum shown. The maximum value is shown for “New Belt” and
new belts should be tensioned at this value to allow for expected tension loss. Used belts should
be maintained at the minimum value as indicated in the table below.
NOTE: The ratio of deflection to belt span is 1:64.
Sheave Diameter - Inches Deflection Force - LBS
Cross
Section
Smallest
Sheave
Diameter
Range
RPM
Range
1000-2500
2501-4000
1000-2500
2501-4000
1000-2500
2501-4000
Used
Belt
3.7
2.8
4.5
3.8
5.4
4.7
5.3
4.5
6.3
6.0
New
Belt
5.5
4.2
6.8
5.7
8.0
7.0
7.9
6.7
9.4
8.9
Used
Belt
4.1
3.4
5.0
4.3
5.7
5.1
4.9
4.2
7.1
7.1
8.5
7.3
New
Belt
6.1
5.0
7.4
6.4
9.4
7.6
7.2
6.2
10.5
9.1
12.6
10.9
860-2500
2501-4000
860-2500
2501-4000
860-2500
2501-4000
Belt Deflection Force
Super Gripbelts and
Unnotched Gripbands
Gripnotch Belts and
Notched Gripbands
3.0 - 3.6
3.8 - 4.8
5.0 - 7.0
3.4 - 4.2
4.4 - 5.6
5.8 - 8.6
A, AX
B, BX
Tensioning V-Belt Drives