Other Features Specific To The Type 4815 - BRUEL & KJAER System V Instruction Manual

6.3.3. Other Features Specific to the Type 4815
The construction of the Type 4815 is sim ilar to that of the Type 4814 in that the force
produced in the Driver Coil is directed to a single mounting point in the center, the upper
radial flexure is one piece and the Driver Coil is formed of aluminum wire. However, the
total peak-to-peak travel is only 12,7 mm (0,5 in).
Magnetic shields are provided to reduce the flux density above the table top . Figs.6.14
and 6.15 are plots of typical steady state flux density as a function of distance above the
table top. The alternating flux density is negligible.
Gauss
30 40 50
mm
Distance above Reference Accelerometer
o
0,5 1,0 1,5 2,0 inches
I
! I
740109
Fig .6. 14. Magnetic flux den sit y above the reference A
ccelerometer.
Type 4801 Body
Gauss
8or---------,----------r---------,----------.---------~
70 r---------~~~~---r--------~----------+---------~
60r---------~---------r--------~~~~~--+---------~
500~--------~10----------2L O--------~30----------4~0--------~50
mm
Distance above Reference Accelerometer
o
0,5 1,0 1,5 2,0 inches
IL-__________
-L!_ _ _ _ _ _ _ _ _ _ _ _
~I
____________
~!
_ _ _ _ _ _ _ _ _ _ _ _
~I
740110
Fig.6. 15. Magnetic flux density above the reference Accelerometer.
Type 4805 Body
42