86517-01-01-01-01 Accelerometer Interface Module

The accelerometer-based transducer system consists of a high-temperature charge-coupled accelerometer; rugged, low-noise, high-temperature extension cable(s); and the accelerometer interface module, as shown below：

86517-01-01-01-01 accelerometer interface module performs the following functions:

1. Converts a charge input from the accelerometer to a voltage acceleration signal.

2. Scales the voltage signal to 10 mV/g peak (1.02 mV/m/s2 pk).

3. Buffers the acceleration signal so that it can be connected to instrumentation over long cable lengths.

4. Bandpass filters the acceleration signal using a 12th-order filter with corner frequencies determined by option BB.

5. Integrates the filtered acceleration signal to a velocity signal with a sensitivity of 100 mV/in/s pk (3.94 mV/mm/s pk).

6. Buffers the velocity signal so that it can be connected to monitoring instruments over long cable lengths. The velocity signal is typically used to monitor machines.

The differential charge output of the accelerometer enters the interface module through pins C and A of the three-pin locking connector, while pin B connects to the extension cable inner shield and to the interface module case. The charge amplifier converts the differential charge input to a low impedance voltage signal, and the subsequent scaling stage adjusts the sensitivity to 10 mV/g pk (1.02 mV/m/s2 pk). The frequency response of the charge amplifier/scaling stage combination has an overall bandpass transfer characteristic. See Section 6 for specifications. The interface module can be ordered to operate with accelerometers having charge sensitivities of 50 pC/g or 100 pC/g. This option is not field programmable.

86517-01-01-01-01 interface module filters are cascaded, 6th order low pass and 6th order high pass filters with a Butterworth response. Filter corner frequencies are determined at ordering and are not field programmable. The corner frequencies are normally chosen to pass the vibration component at the rotative speed of each rotor while excluding higher and lower frequency signals, which may be due to blade passings or structural resonances. The standard corner frequency options conform to requirements for General Electric LM 2500, LM 5000, LM 1600, and LM 6000 series aeroderivative gas turbines. Contact your Bently Nevada representative for nonstandard corner frequencies. If you elect to use corner frequencies not recommended by the engine manufacturer, consideration should be given to the fact that the acceleration signal will contain structural and/or structural-borne noise that is not related to rotor vibration. Most common machine malfunctions originate on the rotor and can be detected as a change in rotor vibration. Choose corner frequencies carefully.

ORDERING INFORMATION：

86517 – AXX – BXX – CXX - DXX

A Transducer Charge Input Sensitivity Option

    01 50 pC/g

    02 100 pC/g

B Filter Corner Frequency Option

    01 25 Hz high pass corner, 350 Hz low pass corner

    02 100 Hz high pass corner, 560 Hz low pass corner

    03 40 Hz high pass corner, 300 Hz low pass corner

C DC Signal Bias Voltage

    01 -10 Vdc, No other option available

D Agency Approval 00 Not Required

    01 Canadian Standards Association 02 CENELEC (SIRA)

Extension Cable：

Softline Cable：

45358 - 07 7 Metre

45358 - 09 9 Metre

Hardline Cable：

83387 - 054 54 inch

             065 65 inch

             096 96 inch

             100 100 inch

             132 132 inch