BRUEL & KJAER System V - Cleaning of Exciter Head; Clean Workbench Surface; Care of Mounting Surface; Exciter Head Inspection and Repair

8.3 .2 . Cleaning of Exciter Head
An Exciter Head should normally require very little cleaning . It is advisable to wipe away
any accumulated grease , dirt. or grime off the Driver Coil just before installing the Exciter
Head each time. If the head is unusually dirty, it may be immersed for a short time in iso-
propyl alcohol or freon and agressively agitated to dissolve any grease and dislodge any
foreign particles .
8.3.3. Clean Workbench Surface
The Exciter Head should be placed on ly on smooth clean surfaces. It is convenient to
have the Exciter Head on a workbench while making a fixture to attach a test object to
the exciter table or when preparing instrumentation for a vibration test. If a sharp object
were on the workbench underneath the Driver Coil, the Driver Coil might get damaged
when the moving element deflects downwards.
8.3.4. Care of Mounting Surface
The user should be very careful to keep the mounting surface of the table clean . The sur-
face is hardened and anodized aluminum , but it could still be scratched if, for example,
sand got in between the table and the fixture. Hence, to prevent scratching the mounting
surface, the table and the lower surface of the fixture should be cleaned before they are
joined.
The lower surface of the test object mounting fixture should be smooth and flat. When -
ever possible , grind this lower surface. A smooth, flat surface minimizes localized
stresses in the mounting surface and provides good vibration coupling from the moving
element to the test object.
8. 3 .5. Exciter Head Inspection and Repair
If something appears to be wrong with the Exciter Head, inspect the coil and the screws
holding the lower flexures to the Moving Element Skeleton by looking into the bottom of
the Head Protective Can.
For
major repairs the Exciter Head should be sent to B & K, Nrerum, Denmark, since pre-
cision a lignment fixtures are necessary.
8.4. CARE OF EXCITER BO DY 48 05
The most important thing with the 4805 is to either have a Head or a cover on at all
times. Since it is a permanent magnet, the magnetic field is always " On" and anything
ferrous that comes within the field will be drawn into the gap.
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