Vibration Meter Reading
Vibration Meter Reading
(OP)
I am in the electronic repair and calibration field, I required to calibrate a vibration meter(3 axial geophone) The calibration is no problem,but I need to convert the units my manager gave me in Vibration mm/s into what my test instrument reads (Voltmeter(mV))
I am using B&K Accelerometer Type 4382 & Charge Amplifier Type 2635. My 3625 Amplifier Setting as follows:
Transducer Sens: 3.21; 1-11 pC/m/s2,10mV/Unit Out
0.2 Acc Lower Freq Limit,
30KHz Upper Freq Limit.
The Amplifier is Connect to the Voltmeter (mV RMS)
Mounted on the Shaker (labworks Duebase Model db-139/140)
Input Freq @ 20Hz - Voltmeter Read Vibration Meter(mm/s)
9.95mV 10.2
8.97mV 9.2
7.98mV 8.1
6.95mV 7.1
6.0mV 6.0
5.0mV 5.1
4.0mV 4.0
3.0mV 3.0
2.0mV 2.0
1.0mV 1.0
Input Freq 80Hz 2.5mV 0.7 mm/s
5.0mV 1.3 mm/s
6.0mV 1.5 mm/s
7.0mV 1.7 mm/s
8.0mV 1.9 mm/s
9.0mV 2.3 mm/s
10.0mV 2.5 mm/s
15.0mV 3.8 mm/s
20.0mV 5.1 mm/s
25.0mV 6.4 mm/s
30.0mV 7.7 mm/s
How to correlate the reading?
Thanks
Peter
I am using B&K Accelerometer Type 4382 & Charge Amplifier Type 2635. My 3625 Amplifier Setting as follows:
Transducer Sens: 3.21; 1-11 pC/m/s2,10mV/Unit Out
0.2 Acc Lower Freq Limit,
30KHz Upper Freq Limit.
The Amplifier is Connect to the Voltmeter (mV RMS)
Mounted on the Shaker (labworks Duebase Model db-139/140)
Input Freq @ 20Hz - Voltmeter Read Vibration Meter(mm/s)
9.95mV 10.2
8.97mV 9.2
7.98mV 8.1
6.95mV 7.1
6.0mV 6.0
5.0mV 5.1
4.0mV 4.0
3.0mV 3.0
2.0mV 2.0
1.0mV 1.0
Input Freq 80Hz 2.5mV 0.7 mm/s
5.0mV 1.3 mm/s
6.0mV 1.5 mm/s
7.0mV 1.7 mm/s
8.0mV 1.9 mm/s
9.0mV 2.3 mm/s
10.0mV 2.5 mm/s
15.0mV 3.8 mm/s
20.0mV 5.1 mm/s
25.0mV 6.4 mm/s
30.0mV 7.7 mm/s
How to correlate the reading?
Thanks
Peter





RE: Vibration Meter Reading
The 2635 can do that, the knob on the right at the bottom allows you to select between accelelration, velocity and displacement. However the sacling is a bit weird, it is worth experiementing with it, I think it uses units of 10 mm/s.
The other option is to scale your 80 Hz figures, 4 times the frequency should give a factor of 4 difference between acceleration and velocity.
If that doesn't answer your question you need to explain a bit more.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Vibration Meter Reading
My manager just me the formula for the calculation.
V = a/2*pi*f
S =V/2*pi*f
V= Velocity,
a= Acceleration
S= Displacement
f= frequency
If I need to measure Velocity - need to turn the dial knob to 1 or 10 Vel.Lower Freq Limit
For Acceleration dial knob set to 0.2 or 2 Acc.Lower Freq Limit.
Best Regards
Peter
RE: Vibration Meter Reading
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.