VNW (Very Narrow Web) transducer is a compact tension sensing device for
measuring process tension in narrow web (up to four inches wide), ribbon
or filament. The VNW transducer combines the robust and versatile design
of DFE's time-proven Model C shaft-end
transducers with a choice of mounting styles and wheel options from the
RFA -style cantilevered transducers. DFE has kept the quality of the VNW
transducer high while offering it at a highly competitive base price.
A VNW transducer is cantilever-mounted on process machinery for unwind,
payoff, rewind, take-up, or intermediate zone applications. Tension is
measured by high-output silicon strain gages housed internally on a dual
cantilevered transducer beam and connected in a wheatstone bridge configuration.
As the ribbon or filament passes over the rotating transport wheel, the
force of the substrate on the wheel shaft causes a minute deflection of
the transducer beam. The resulting change in strain gage resistance yields
a voltage output from the transducer that is proportional to tension.
The transducer output is then amplified by a DFE indicator or automatic
controller for tension measurement or complete closed-loop tension control.
VNW transducer's standard configuration has an aluminum beam with a stainless
steel housing and shaft holder. The five mounting styles offered are single
bolt (with an alternative to face-mount the transducer on the opposite
side of the machine frame using a bolt pattern on the transducer front),
flange, pillow block, piloted flange, or through-frame.
All wheels are optional accessories; no wheel is provided as standard
since many customers prefer to supply their own shafts and wheels. Wheels
are shaft-mounted with the shaft inserted into the transducer's face coupling
and secured by set screws. The shaft insertion depth can be adjusted (+/-
0.25 inch) for proper alignment of the wheel with the web. On the standard
unit the electrical connector is positioned at 6 o'clock (same as the
tension force direction).