VNW Tension Transducers

The 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.

The 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).