Nexen MB25B 911996 - Manual (Page 4)

FORM NO. L-20127-L-0513 4
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
Pillow
Block
Web
Load F
Pivot
Point
Load
Plate
Transmission
Plate
Main
Spring
Core
LVDT
Coil