Pulley / Sheave Alignment & Belt Tension - Quincy Compressor QT Series Instruction Manual

Pulley / Sheave Alignment & Belt Tension
QT/QTS Series
2022208700, September 2018
Improper pulley/sheave alignment and belt tension are causes for mo tor
overloading, excessive vibration, and premature belt and/or bearing failure.
To prevent this from happening, check the pulley/sheave alignment and belt
tension on a regular basis (refer to SECTION 5, Maintenance Schedule).
Periodically inspect the motor pulley(s) and compressor sheave(s) for oil,
grease, nicks or burrs. Clean or replace if necessary. Make sure they are securely
fastened. Align the compressor sheave with the motor or engine pulley. Drive
belt grooves of the pulley(s) and sheave(s) should be in line with each other.
The compressor crankshaft must be parallel to the motor or engine drive shaft.
Belt tension should be measured and adjusted to provide smooth op eration.
Step-by-step procedures are provided here to correctly measure and set the
drive belt tension:
Step 1) Measure the span length of the drive. (Refer to Fig. 5-1, Setting
Belt Tension.)
Belt Motor Pulley
Cross Dia. Range
Section
A QTS-3, QTS-5 & QT-54
B
B
B
B
Step 2) Determine the amount of deflection ( in inches) required to measure
de flection force (in pounds) by multi plying the span length x
(.016) (i.e. 32" span length x
to measure de flection force).
38
Fig. 5-1
Setting Belt Tension
Deflection Force (lbs.)
(inches) Minimum
4.6
5.0 - 5.4
5.6 - 6.4
6.8 - 9.4
/ [.016] =
1
64
Recommended
Maximum
2 3
4.0 5.9
4.5 6.7
5.0 7.4
5.8 8.6
/ "[.50] of deflection required
1
2
Quincy Compressor
/
1
64