NVH for Belt tension measurement

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volrem
TwoWaves
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Location: Estonia

NVH for Belt tension measurement

Post by volrem » Sat Oct 26, 2019 3:29 pm

Hi


Has anyone used a Pico NVH kit to measure belt tension? Don't want to but 1000 EUR tool and use it once a year if I can do it with my NVH kit.

I need it for auxiliary drive belt tension measurement on PHEV application. Target frequency is 170-180 Hz.

Seen videos where frequency is measured with smartphone on timing belts with Guitar tuner apps.
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Steve Smith
Pico Staff Member
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Joined: Sun Aug 25, 2013 7:22 am

Re: NVH for Belt tension measurement

Post by Steve Smith » Mon Oct 28, 2019 9:18 am

Hello Volrem and thank you for the post
This post may be of some interest too here

Most certainly yes, you can use either NVH or PicoScope (Time Domain/Spectrum Mode) to capture the frequency of a strummed belt and then apply the obtained frequency into a formula top denote the tension:

Below is an NVH narrated capture using the TA144 NVH Mic that I hope will help
Image 1.png
Image 1
TEST 2 AUX BELT MIC SECURED WITH NARRATION.pddata
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As you can see above, the frequency of the strummed serpentine belt is approx. 195 Hz and this is regardless of strumming force or where you strike the belt.(Where possible strum the belt from the center of the longest accessible span)

The obtained frequency can now be incorporated into a formula provided by the belt manufacturer.

I know from experience obtaining the frequency measurement is both accurate and easy with Pico, what is challenging is obtaining the correct data for the belt under test.

Ideally refer to the belt manufacturer for the formula as identical belts from different manufacturers will have differing constructions/mass, therefore different formulas to derive tension from frequency.

For example, measuring a Gates belt, use the Gates formula based on Gates belt technical data from their website

Formula: T = 4 x S(squared) x M x W x f(squared) x 10-9

Where: T = belt span tension (Newton)
S = length of the span to be measured (mm)
M = belt unit weight (g/m/mm)
f = natural frequency of the belt (Hz)
W = belt width (mm)

I hope this helps, take care......Steve

Steve Smith
Pico Staff Member
Pico Staff Member
Posts: 729
Joined: Sun Aug 25, 2013 7:22 am

Re: NVH for Belt tension measurement

Post by Steve Smith » Mon Oct 28, 2019 5:19 pm

Many thanks to Ben for the reminder here:

In our Guided Test menu under the Automotive Tab we have a Belt Tension test using PicoScope
BELT TENSION.png
Image 1
Here we review the data in both the Time and Frequency Domains

Please take a look at the "Further Guidance" section within the Guided Tests too

Take care......Steve

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