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Gracey & Associates Hire

Bruel & Kjaer UA 0559



B&K UA 0559 Mechanical Filter for Accelerometers£ 2 a day *


  • Uses
  • General vibration measurements, particularly where instrumentation is not equipped with a choice of low-pass filters
  • Measurement of low frequency, low level vibration which is masked by high frequency, high acceleration levels often found in hand-held-power tools.
  • Protection of accelerometer and preamplifier from high level shocks
  • Reduction of sensitivity to transverse vibrations
  • Features
  • Prevents the accelerometer from detecting high frequency vibration
  • Prevents the excitation of accelerometer resonance
  • Usable with all types of piezoelectric accelerometers
  • Cut-off frequency selected by adjusting the load mass
  • Breaks ground-loop paths

Mechanical Filter UA 0559 is interposed between an accelerometer and the mounting point on the test object in order to prevent the accelerometer from detecting high frequency vibration. There are several instances where this may be desirable:

1) Where it is wished to measure low frequency vibration, possibly at low levels, and where high level, high frequency acceleration masks the low frequency components because of preamplifier overload, distortion, lack of electronic filters etc.

2) Where the accelerometer resonance frequency is being excited by high frequency vibration of possibly insignificant level, causing wide band measuring errors and overload. Thus by using the mechanical filter the useful dynamic range of measuring instruments is increased by more than 20 dB.

3) Where it is feared that the accelerometer could be subjected to transient shock levels beyond its maximum capability, thus preventing damage.

4) Where the measuring instrumentation has a high frequency response in excess of that required and is not equipped with suitable low-pass filters. Vibration measurement with a wide-band sound level meter is a notable example of this case.

5) Where it is wished to obtain a specific cut-off frequency without the use of specially built electronic filters or elaborate tunable filters. For example, when measuring vibration as applied to the human hand, arm or body, the measuring range is normally limited to below 1000 Hz.


Mechanical Description
The filter consists of an upper and lower part of stainless steel bonded together and electrically separated by a specially formulated butyl rubber core. The two halves are equipped with standard accelerometer threads (10 - 32UNF), male and female respectively. A tommy bar can be inserted transversely through the two halves to relieve the rubber core of excessive twisting torque when the accelerometer is tightened down. Where the butyl rubber core can be contaminated with hydrocarbon substances such as oil or fuel, a resistant silicone rubber sealer should be used (e.g. Dow Corning Type 733 RTV).


Manufacturer's Specifications

Delivered with a B&K DA 1084 Tommy Bar



* Our standard hire charges are based on a 7-day minimum period. Click here for details and other options.

Gracey and Associates   01933 624212
BSI approved for the hire of noise and vibration instruments
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