Binsfeld TorqueTrak 9000, User Manual, Page: 17 / 35

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(V
FS
)(

)(E)(4)(D
o
4
-D
i
4
)
= T
FS
(N-m)
(V
EXC
)(GF)(N)(16000)(1+

)(G
XMT
)(D
o
)
C1: Torque on Round Shafts
Step 1: Calculate Full Scale Torque, T
FS
(ft-lb) that corresponds
to the maximum system output of 10.0V.
For a solid steel shaft, use this simplified equation:
For all other shafts use the more general equation:
Legend of Terms
D
i
Shaft Inner Diameter (in) (zero for solid shafts)
D
o
Shaft Outer Diameter (in)
E Modulus of Elasticity (30 x 10
6
PSI steel)
GF Gage Factor (specified on strain gage package)
G
XMT
Telemetry Transmitter Gain (user configurable, typical
is 2000 for ±500 microstrain range; See Appendix E)
N Number of Active Gages (4 for torque)
T
FS
Full Scale Torque (ft-lb)
V
EXC
Bridge Excitation Voltage = 5 volts
V
FS
Full Scale Output of System = 10 volts
 Poisson’s Ratio (0.30 for steel)
For metric applications with D
o
and D
i
in millimeters and T
FS
in
N-m the general equation is:
Where E= 206.8 x 10
3
N/mm
2
.
(755.17 x 10
3
ft-lb/in
3
)(D
o
3
)
= T
FS
(ft-lb)
(GF) (G
XMT
)
(V
FS
)(

)(E)(4)(D
o
4
-D
i
4
)
= T
FS
(ft-lb)
(V
EXC
)(GF)(N)(16)(1+

)(G
XMT
)(D
o
)(12)