Fiber optic Accelerometer - HFOA

Accelerometers are normally used as integral components of equipment monitoring and diagnostic systems to detect abnormal operation of a machine. However, environmental conditions often preclude the use of piezo-electric or piezo-resistive accelerometers because of their conventional electrical sensing element and transmission.

The HFOA Fiber Optic Accelerometer is by design nonconductive and immune to electromagnetic interferences. Fiber optic link ensures an excellent electrical insulation between the sensor and the instrumentation. Its passive principle makes it ideal for shock and vibration measurements in areas where conventional accelerometers may create electrical discharges, cause changes in magnetic field distribution, prove hazardous to personnel, and impair reliable operation. It can be used in numerous applications including rotating machinery, high voltage transformers, circuit breakers, high voltage electrical transmission lines, explosive atmospheres, etc.




Online vibration monitoring in hazardous areas 

High voltage, severe electromagnetic interferences and highly explosive gas.
Electrical machine (trubo-generators, hydro-generators, motors) End-windings, windings and stator teeth.
Electrical motor brushes.
Isolated turbo-generator bearings.
High voltage circuit breakers.



- Electrical insulation exceeding 27 kV between sensor head and conditioning electronics.

- Lightweight non-metallic sensor head approx. 20 grams..
- Unsensitive to magnetic and electrical field.
- Low transversal sensitivity.
- Very good thermal stability.
- Two integral cable lengths: 6m and 10m, other lengths on request.

- Sealed feethrough connector / conditioner.


Technical data 

Frequency range

30 Hz to 350 Hz +/- 5 %, up to 950 Hz on request.

Resonance frequency

> 500 Hz

Dynamic range

0...40 g (0...1 mm pk-pk @ 100 Hz)

Output sensitivity

100 mV / g, single ended DC coupling, bias voltage +6 VDC

Power supply

24 VDC +/- 20 %, approx. 40 mA

Transverse sensitivity

< 5 % of axial

Residual noise

< 3 mVRMS overall noise between 30 and 350 Hz


< 1 mm pk-pk @ 100 Hz

Insulation voltage

> 27 kVRMS @ 50 Hz between sensor head and electronics

Operating pressure

5 bar


Operation sensor


Non-destructive sensor


+90 0C max.

0...70 0C -20...100 0C -20...85 0C

Magnetic field

1 tesla RMS @ 50 Hz max.

Electrical field

1 MV / m @ 50 Hz max.


Sensor body Sealed feedthrough Integral cable

PPO Noryl and ceramic, 25 (L) x 18 (W) x 18 (T) mm, weight 30 grams.

Chromed brass alloy, S12 4-Pin connector on outside end with mating metallic shielded connector, Viton O-ring 21.95 x 1.78, 2 hex nuts M18 x 1, 92 mm length with 35 mm thread, max. diameter 28 mm, weight 120 grams. 3 fiber glass strands with PTFE protection tubing, 6 m or 10 m length, diameter 5 mm, 80 mm bending radius min.