Gravitational effects, Gravitational charts, Free air correction for altitude – CDI Torque SURETEST Torque Calibration System User Manual
Page 57
MANUAL LOADER
CHAPTER 6
6-56
Gravitational Effects
Correction Factors on Test Weights
Weights used in torque calibration are affected by their acceleration due to:
•
Altitude above or below sea level, and
•
Latitude on earth between the equator and the poles.
Test bars are not affected by these conditions. The accuracy of torque wrenches
and testers does not change due to changes in geographic location. Only when
using weights must correction factors be considered. After an analysis is made
for a given location, it is often found that the correction factor is insignificant.
Two methods of correction are provided. They are:
•
Correction factor for check point readings adjusts the calibration readings
without changing the applied weight.
•
Correction factor for weights adjusts the weight applied without changing check
point readings. For additional information refer to Gravitational Charts in this
chapter.
Gravitational Charts
The charts in this section are taken from CRC Handbook of Chemistry and
Physics, 58th Edition. CRC Press, Inc., 18901 Cranswood Parkway. Cleveland,
Ohio 44128.
Acceleration Due to Gravity for Sea Level at Various
Latitudes
Latitude, degrees
Acceleration, cm/sec2
Latitude, degrees
Acceleration,
cm/sec2
0
978.039
46
980.711
5
978.078
48
980.892
10
978.195
50
981.071
15
978.384
52
981.247
20
978.641
54
981.422
25
978.960
56
981.592
30
979.329
58
981.757
32
979.487
60
981.918
34
979.652
65
982.288
36
979.822
70
982.608
38
979.995
75
982.868
40
980.171
80
983.059
42
980.350
85
983.178
44
980.531
90
983.217
Free Air Correction for Altitude
Altitude,
m
Correction,
cm/sec2
200 -0.0617
300
-0.0926
400
-0.1234