Maximum Allowable Drive Train Misalignment; Driver To Compressor Free Coupling Alignment - GE H301 Series Operating Manual

44 | Chapter 4: Installation
Frame model series
H302
Compressor frame thermal growth
Ta ble 13
For example: 12.315 x 0.0000058=0.00007 0.00007 x 100°F=0.007"
The tabled compressor frame thermal growth figures are
based upon a 100°F (38°C) temperature rise and use a cast
iron thermal expansion coefficient of 0.0000058 inch/ inch/

maximum allowable Drive Train misalignment

An HSR compressor drive train must be properly aligned for its normal (hot)
operating condition.
The maximum allowable hot total indicator run out (TIR) is
0.005" (0.127 mm) for both angular (face) and parallel (radial)
misalignment when using a 12" (305 mm) diameter coupling.
Since the compressor and its driver seldom have the same shaft center line height
and operating temperature, the drive train is often misaligned for its ambient
(cold) condition. Check the drive train's alignment and adjust as required, during
compressor installation and after startup for its normal (hot) operating condition.
Typically the compressor (with its attached piping limiting it
movement) is considered the fixed piece in the drive train,
with the driver being the movable component for realignment
purposes. The Packager's design and installation practices
will determine the initial cold offset between the driver and

Driver to Compressor Free Coupling alignment

Use the "free coupling" method to minimize alignment inaccuracies, since one
end of the coupling is unrestrained. Refer to
arrangement and which coupling hub bolts to remove.
Indicator R measures the radial misalignment or parallel offset. Indicator A
measures the axial or angular misalignment.
Center line height (nominal)
Inches (mm)
12.3125 (312.7375)
°F.
Complies with ANSI Z535, ISO 3864, OSHA 1910.145 (f) (9)
Complies with ANSI Z535, ISO 3864, OSHA 1910.145 (f) (9)
the compressor.
Complies with ANSI Z535, ISO 3864, OSHA 1910.145 (f) (9)
"Figure 9"
Thermal growth
Inches (mm)
0.007 (0.178)
for the dial indicator