Snap-on Motorized Loader Manuale Utente Scaricare il pdf (Pagina 71)

5-11

Calibration

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 Acceleration Latitude Acceleration

Degrees cm/sec2 Degrees 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

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Snap-on Motorized Loader Manuale Utente Pagina 71