BRUEL & KJAER System V - Rotation Clamp Knob

4.3.6. Rotati on Clamp Knob
4.4.
4801 (S)
The larger of the two knobs in the top center of the Side support is the Rotation Clamp
Knob . When this knob is rotated clockwise, the Rotation Brake expands and rotation of
the exciter relative to the Side Support is prevented . This knob should always be in the
clockwise tight position when the exciter is operated .
A
steel plate base, without suspension system or trunnion mechanism , is available for
the 4801 Exciter Body. See Fig.4. 5. The Exciter Body Type 4801 fitted with the fixed
base is designated Type 4801 S.
Fig.4 .4 . Exciter Body Type 4801 S with Head Type 4811
This simplified base can be used for supporting the exc iter body in the normal way on the
floor but the lack of suspension and overall stiffness makes it unsuitable for applications
where purity of motion is critical .
The fixed base is mainly intended for applications where the suspension / trunnion system
would be redundant, for example, the excitation of large structures to determine resonant
modes , mechanical impedance or transmissibility. Here the exciter is often slung from
ropes. Where the exciter is to be used on a seism ic block of low resona nt freq uency, the
suspension system integral with the standard base is not necessary.
For customers who initially purchase the Exciter body fitted with the Fixed (S) base and
later wish to convert to the standard base (T). this is available as a separate item (KS
0031) on req uest.
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