Theory of operation, Mb41 – Nexen MB25B 911996 User Manual

Page 4

FORM NO. L-20127-L-0513

MB Tension Sensors are available in seven force ranges, divided into five frame sizes: MB05, MB11, MB25, MB33,
and MB41. MB05, MB11, MB25, and MB33 utilize a torsion bar for both Pivot Point and load resistance. Because of
the greater forces involved, MB41 utilizes a conventional resistance spring type construction rather than the torsion bar.

MB05, MB11, MB25, and MB33

Force applied perpendicular to the Load Plate causes the
plate to rotate about the Pivot Point (See Figure 1). This
movement causes a change in the position of the Core
within the coil of the LVDT (Linear Variable Differential
Transformer). The coil is excited by input voltage from
the Tension Controller or Tension Meter. Its output varies
directly with any change in Core position. Movement of
the Load Plate is opposed by a torsion bar, which also
forms the Pivot Point.

MB41

Force applied perpendicular to the Load Plate causes the
plate to rotate about the Pivot Point (See Figure 2). This
movement causes a change in the position of the Core
within the coil of the LVDT (Linear Variable Differential
Transformer). The coil is excited by the input voltage from
the Tension Controller or Tension Meter. Its output varies
as the position of the Core changes. The movement of
the Load Plate is opposed by the Main Spring which is
connected to the Load Plate by the Transmission Plate.

THEORY OF OPERATION

FIGURE 1

Sensor
Roll

Load F

Pillow
Block

Web

LVDT
Coil

Core

Load
Plate

Pivot
Point

FIGURE 2