Sterlco TG 1200 Series Thermoform Granulators - Manual (Page 23)

T-Series Thermoforming Granulators Maintenance 23 of 37
5-5 Adjusting Belt Tension
For continuous reliable operation of the granulator, it is important that the belt tension is
correct. Correct tension reduces wear on rotor and motor bearings and keeps belt slip to a
minimum. Figure 7 gives the recommended force to deflect each belt by an amount equal to
the belt span divided by 64. A gauge is available through the sales department to measure the
deflection and force. Use the following procedure to adjust the belt tension:
Tension new belts at the maximum run-in force, and check the tension at least two times
during the first two days of operation. There is normally a rapid decrease in the tension until
the belts are run in.
Note: The deflection force value shown must be multiplied by the number of V-belt
elements.
1. Turn off the granulator at the main isolator switch and remove fuses.
2. Remove the belt guard to gain access to the belts.
3. Determine the type of belt required from the Spare Parts List on page 34.
4. Determine the force required to deflect one belt 1/64” (0.40 mm) per 1 inch (25.4
mm) of span length.
5. Loosen the motor base slide mount screws and turn the adjusting screw on the base to
tension the belts as required (See Figure 7).
6. Re-tighten the screws, making sure the sheaves are in correct alignment.
7. Replace the covers.
Figure 7: Belt Tensioning Information
Recommended Deflection
Force (Lbs.)
V-Belt
Cross
Section
Small Sheave
Diameter
Range
(Inches)
Small Sheave
RPM Range
Speed Ratio
Range
Run-In Normal
Running
B 3.4
4.6
5.0-5.2
5.4-5.6
6.0-6.8
7.4-9.4
1160 to 1800 2.0 to 4.0 5.4
7.4
8.5
9.1
10.0
12.0
3.8
5.1
5.8
6.2
7.1
8.1
BX 3.4
4.6
5.0-5.2
5.4-5.6
6.0-6.8
7.4-7.9
1160 to 1800 2.0 to 4.0 7.4
10.0
11.0
11.0
11.0
12.0
5.2
7.1
7.3
7.4
7.7
7.9
*This deflection force value relates to a single V-belt element. Therefore, if the belt is a 3-V
element (3V-banded), this value must be multiplied by 3.
Deflection = Belt Span
64
Belt Span=37”