Hello!!
Where can I find a good and not too expensive load cell??
Load cell
5 posts
• Page 1 of 1
by bruce » Sun Nov 14, 2004 10:34 am
eBay would be a good place to look for one. (I'll assume here that you are looking for an electronic one?) They come up all the time and prices are reasonable. What size do you need? Are you looking for an "S" style?
A hydraulic one can be made out of an old hydraulic cylinder or air cylinder. I plan on using an old 1-1/8" dia air cylinder I have here for my spring tester project if and when I get around to it.
A hydraulic one can be made out of an old hydraulic cylinder or air cylinder. I plan on using an old 1-1/8" dia air cylinder I have here for my spring tester project if and when I get around to it.
"There is no more formidable adversary than one who perceives he has nothing to lose." - Gen. George S. Patton
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by 84-1074663779 » Mon Nov 15, 2004 7:11 pm
Buying a strain gauge is possible, but you will also require the amplifier electronics to go with it, definitely not a low cost solution.
If you are like many of us on a slim budget, there is a more practical way to do it. Fit a suitably rated spring to your torque arm to give a known deflection under load. Attach a fine stranded stainless steel wire to the end of arm, and wrap it several times around a drum. Use a long tension spring to keep the wire tight on the drum. As the torque arm moves, the drum rotates.
Fit a potentiometer to the drum, fed from a stable regulated voltage source, and then measure the voltage change at the potentiometer rotor with a digital voltmeter.
With a bit of experimentation with arm length, spring rating, drum diameter, and voltage, you can make a digital readout display directly in the required torque units. The same output voltage can also be used for data logging or power calculation.
Do not despise this method, many expensive commercial dynamometes still do it this way. It has the advantage of simplicity, and if built to a high standard and properly set up, can be extremely accurate and repeatable. It can also be fabricated at about zero cost by just about anyone.
If you are like many of us on a slim budget, there is a more practical way to do it. Fit a suitably rated spring to your torque arm to give a known deflection under load. Attach a fine stranded stainless steel wire to the end of arm, and wrap it several times around a drum. Use a long tension spring to keep the wire tight on the drum. As the torque arm moves, the drum rotates.
Fit a potentiometer to the drum, fed from a stable regulated voltage source, and then measure the voltage change at the potentiometer rotor with a digital voltmeter.
With a bit of experimentation with arm length, spring rating, drum diameter, and voltage, you can make a digital readout display directly in the required torque units. The same output voltage can also be used for data logging or power calculation.
Do not despise this method, many expensive commercial dynamometes still do it this way. It has the advantage of simplicity, and if built to a high standard and properly set up, can be extremely accurate and repeatable. It can also be fabricated at about zero cost by just about anyone.
- 84-1074663779
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