Accelerometer Selection

In order to achieve optimum measurement conditions the following questions should be answered:

Can you make at the selected location unadulterated measurements of the vibration and derive the needed information?
Does the selected location provide a short and rigid path to the vibration source?
Is it allowable (considering warranty restrictions) and possible in technical respects to prepare a flat, smooth, and clean surface with mounting thread for the accelerometer?
Can the accelerometer be mounted without altering the vibration characteristics of the test object?
Which environmental influences (heat, humidity, EMI, bending etc.) may occur?

The following table shows a summary of the most important criteria for selecting an accelerometer:

Criteria

Accelerometer Properties

Amplitude Range

Choose appropriate sensitivity and maximum acceleration.

Use high sensitivity accelerometers for lowest vibration.

Selection chart for acceleration:

<10 g	10 - 200 g	200 - 1000 g	1000 - 10000 g
KB12(VD) KS48C	KS76C100 KS77C100 KS78.100 KS901.100 KS813B KS74C100 KS80D KS94B100 KS95B100 KS943B100 KS823B	KS76C10 KS77C10 KS78.10 KS901.10 KD41 KD42 KS91B KS94B10 KS95B10 KS74C10 KS943B10	KS93 KD37 KD38 KS56 KS57 KS90

Frequency Range

Choose resonant frequency and linear frequency range

Selection chart for upper 3 dB frequency limit:

<200 Hz	0.2 - 10 kHz	10 - 15 kHz	15 - 25 kHz	>25 kHz
KB12(VD)	KS48C KS813B KS823B	KD37 KD38 KD41 KD42 KS80D	KS76C100 KS77C100 KS78.10/100 KS901.10/100 KS90 KS93 KS943B10 KS943B100 KS74C10 KS74C100 KS56 KS57	KS91B KS94B10 KS94B100 KS95B10 KS95B100 KS76C10 KS77C10

Weight of Test Object

Accelerometer weight <1/10 the weight of test object.

Test method for accelerometer weight to ISO 2954:

"Double de co-vibrating mass of the sensor by an additional mass. If the new indication shows a deviation from the original reading of more than 12%, the mass of the accelerometer is too great."

Choose miniature accelerometers for light objects.

Selection chart for sensor weight:

<3 g	3 - 20 g	20 - 50 g	50 - 100 g	>100 g
KS91B KS94B10 KS94B100 KS95B10 KS95B100	KS90 KS943B10 KS943B100 KS78.10/100 KS901.10/100	KS76C10 KS76C100 KS77C10 KS77C100 KD37 KD38 KS74C10 KS74C100 KS56 KS57	KD41 KD42 KS80D	KB12(VD) KS48C KS813B KS823B

High temperature

Models KS56 and KS57 for up to 250 °C

Temperature Transients, Base Strain, Magnetic Fields, Extreme Acoustic Noise

Assess influence, choose sensor according to characteristics,
choose shear type accelerometers when temperature transients or base strain may occur, stainless steel versions for strong magnetic fields

Humidity and Dust

Industrial accelerometers with protection grade IP67

Measurement of Vibration Velocity and Displacement

Single and double integration, below 20 Hz use shear type accelerometers

Mounting

Quick measurement below 1 kHz with low accuracy	Use accelerometer probe
For temporary measurement without altering the test object	Use magnetic clamp, wax or adhesives
Long-term measurement	Use stud mounting or insulating flange
Grounding problems, potential differences	Use insulating flange or insulated accelerometers
Long distance between sensor and instrument	Use IEPE accelerometers
Measurement in two or three axes	Use triaxial accelerometers or triaxial mounting cubes
Sensor telemetry and battery-powered equipment	Use charge accelerometers or Low Power IEPE accelerometers

Proceed to chapter Accelerometer Mounting

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Accelerometer Selection