Testing F motors on loadcell setup

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lsmith
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Testing F motors on loadcell setup

Postby lsmith » Sun Sep 22, 2019 11:04 pm

Hi guys,

Just a general question. We're measuring thrust curves of particular motors available at hobbie stores for the purpose of simulation modelling, and cross checking consistency between the manufacturers thrust curve and our own for validation. The motors will be pinned and the thrust will be pointing down to the ground with a wooden frame and plywood sheets for containment for safety. All tests are done outside, the largest motor tested is an F (BP). I just want to be sure that what we're doing is ok, would be happy to provide some further information on this.

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Re: Testing F motors on loadcell setup

Postby strud » Mon Sep 23, 2019 8:45 am

Sounds good to me !

The larger BP motors are more prone to failure ie over pressurisation, hence the plywood shield and being away from 'people' would be wise.

What DAQ system and loadcell are you using?

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OverTheTop
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Re: Testing F motors on loadcell setup

Postby OverTheTop » Mon Sep 23, 2019 2:50 pm

Sounds reasonable to me too. Just wondering why you have the motor facing down instead of up? Curious.
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lsmith
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Re: Testing F motors on loadcell setup

Postby lsmith » Tue Sep 24, 2019 8:06 pm

Sorry about the late reply, I am still trying to get used to this forum.

I am using a HX711 board, rewired to take 80Hz instead of 10Hz which is plenty enough. The loadcell I am using is a 20kg beam (link below) connected to a LCD screen that displays the mass on the beam for calibration purposes that I will configure through an arduino. It's all setup on a steel frame and it works a treat. The reason why I have pointed it down is purely for safety reasons so I can minimize any risks and the code has a tare feature so the orientation doesnt affect the results. The way the frame is built works as a launch pad aswell so I am killing two birds with one stone here.

20kg loadcell - (https://www.robotgear.com.au/Product.as ... ZMEALw_wcB)

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Re: Testing F motors on loadcell setup

Postby Voyager » Thu Oct 03, 2019 11:36 pm

What you're doing seems quite reasonable. Our group has used a similar loadcell setup for several tests we've conducted over the last couple of years to make similar BP motor comparisons. It has provided some very useful data.

This setup uses an Arduino with an LCD shield interfaced to a 10 kg loadcell via a suitable amplifier, as shown in the image below. The motor is held inverted in a tubular clamp (not shown) by the two bolts on the free end of the loadcell. The electronics enclosure is covered with a Nomex blanket during each test.

loadcell-1.JPG
loadcell-1.JPG (62.07 KiB) Viewed 202 times
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Re: Testing F motors on loadcell setup

Postby Voyager » Fri Oct 04, 2019 1:48 pm

I should add that the "suitable amplifier" is in fact a HX711 module, too.

Just a suggestion, but this thread could be better off in the Technical > Electronics section of the forum. It is an interesting topic and could develop further.
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