National Crane 3-29-2018 Control # 610-00 3-17
NBT40-1 SERIES OPERATOR MANUAL SAFETY INFORMATION
This situation will also occur in reverse. If equipment is set up
in the morning with cool oil and the daytime ambient
temperature heats the oil, the cylinders will extend in similar
proportions.
Table 3-2 and Table 3-3 have been prepared to assist you in
determining the approximate amount of retraction/extension
that may be expected from a hydraulic cylinder as a result of
change in the temperature of the hydraulic oil inside the
cylinder. The chart is for dry rod cylinders. If the cylinder rod
is filled with hydraulic oil, the contraction rate is somewhat
greater.
NOTE: Operators and service personnel must be aware
that load movement, as a result of this phenomena,
can be easily mistaken as leaking cylinder seals or
faulty holding valves.
Table 3-2: Boom Drift Chart (Cylinder length change in inches)
Table 3-3 Boom Drift Chart (Cylinder length change in millimeters)
Coeff. = 0.00043
(in
3
/in
3
/ °F)
STROKE Temperature Change (°F)
(FT.)102030405060708090100
5 0.260.520.771.031.291.551.812.062.322.58
10 0.52 1.03 1.55 2.06 2.58 3.10 3.61 4.13 4.64 5.16
15 0.77 1.55 2.32 3.10 3.87 4.64 5.42 6.19 6.97 7.74
20 1.03 2.06 3.10 4.13 5.16 6.19 7.22 8.26 9.29 10.32
25 1.29 2.58 3.87 5.16 6.45 7.74 9.03 10.32 11.61 12.90
30 1.55 3.10 4.64 6.19 7.74 9.29 10.84 12.38 13.93 15.48
35 1.81 3.61 5.42 7.22 9.03 10.84 12.64 14.45 16.25 18.06
40 2.06 4.13 6.19 8.26 10.32 12.38 14.45 16.51 18.58 20.64
45 2.32 4.64 6.97 9.29 11.61 13.93 16.25 18.58 20.90 23.22
50 2.58 5.16 7.74 10.32 12.90 15.48 18.06 20.64 23.22 25.80
55 2.84 5.68 8.51 11.35 14.19 17.03 19.87 22.70 25.54 28.38
60 3.10 6.19 9.29 12.38 15.48 18.58 21.67 24.77 27.86 30.96
Length change in inches = Stroke (Ft.) X Temperature Change ( °F) X Coeff. (in
3
/in
3
/ °F) X 12 in/ft
Coeff. = 0.000774
(1/ °C)
STROKE Temperature Change (°C)
(m) 5 10 15 20 25 30 35 40 45 50 55
1.5 6 12 17 23 29 35 41 46 52 58 64
3 1223354658708193104116128
4.5 17 35 52 70 87 104 122 139 157 174 192
6 23 46 70 93 116 139 163 186 209 232 255
7.5 29 58 87 116 145 174 203 232 261 290 319
9 35 70 104 139 174 209 244 279 313 348 383
10.5 41 81 122 163 203 244 284 325 366 406 447
12 46 93 139 186 232 279 325 372 418 464 511
13.5 52 104 157 209 261 313 366 418 470 522 575
15 58 116 174 232 290 348 406 464 522 581 639
16.5 64 128 192 255 319 383 447 511 575 639 702
18 70 139 209 279 348 418 488 557 627 697 766
Length change in mm = Stroke (m) X Temperature Change ( °C) X Coeff . (1/ °C) X 1000 mm/m
Metric