Binsfeld TorqueTrak 10K-LP, User Manual

Page: 37 / 45

- 35 -
B2: Axial Strain on Round Shafts
Step 1: Calculate Full Scale Forces P
FS
(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 4000 for ±770 microstrain range)
P
FS
Full Scale Force (tension or compression) (lb)
TX
const
Transmitter constant = 2.5 volts
V
FS
Full Scale Output of System = 10 volts
 Poisson’s Ratio (0.30 for steel)
(V
FS
)(

)(E)(D
o
2
-D
i
2
)
= P
FS
(TX
const
)(GF)(2)(1+

)(G
XMT
)
(145 x 10
6
lb/in
2
)(D
o
2
)
= P
FS
(GF) (G
XMT
)