Position: The Question:
I need to measure the force produced by a thruster. I bought a single point load cell and I intend to use a pin fixed in the thruster to press on the load cell and perform strain. This is the load cell I have:
http://www.amcells.com/Products_Deta...t/SPS/SPS.html
The problem is that I don't know where to place the load pin on the single point load cell. I don't have a user manual (nor a calibration chart!). An arrow shows the "direction" of applying load, I need to know the "location" of applying the load.
There are 4 places for bolts distributed 2 at each side. Should all these be used to fix the load cell in the test stand and then apply the load at the center? This doesn't seem right as there is a soft material in the middle (that is probably used to cover the strain gauges).
Should I fix the load cell from one end and apply the load from the other end (i.e. cantilevered style)?
In either cases should the load be concentrated or should I try to distribute the load over the applied area?
Answer 1
What is the capacity and "Group" of the load cell you bought? .
Single point load cells are cantilever cells.
The single point load cell is bolted at the cable side (to floor) and the otherside will have a pan attached to it.(Like the retail scales you see i departmental store!).
Most low capacity single point cells can take a platform size of 300*400mm(around 500 mm diagonally). Please check with manufacturer for the eccentic load capability.
Can you please explain your application in detail. Single point cells are made of Alumnium and have a large deflection like 0.5mm at full load. This basically means that it has low natural frequency.
Is response time an important factor in your application.
Answer 2
I am Opsens application engineer and we did thrust measurements in the past with various cases (small scale models and space shuttle case). In order to fully understand you application, I think that I would need to talk with you over the phone.
Looking at the bottom of the page you linked to, the drawing shows the weighing application area as "E" and the other end is mounted on a fixed point.
You might see an arrow there, pointing in the POSITIVE weight direction.
Answer 3
You might have been better served with a button type, maybe having been confused by the "single point" terminology. With the button or round fixed type with center bolts, it is more easily mounted.
http://www.sensotec.com/loadcell.asp?category=mini
