Measuring Magnetic Moment of a Torque Rod

[Kydharis]

Hello everyone,

I am working on producing a torque rod (basically a solenoid) for use in a spacecraft that I am working on here at University of Colorado, Boulder.

My requirement for this torque rod is to produce at least 7.7Am^2 of magnetic torque. Currently, I have made a torque rod that theoretically can generate this torque, with something like 11,000 turns with a set diameter, material, etc...

The problem I am having is actually validating that this torque rod I have made meets the 7.7Am^2 requirement. I have used a gaussmeter to attempt to measure this, but when converting a magnetic flux measurement to a magnetic moment, it is extremely sensitive to radius. The calculation I used to convert to a magnetic moment is also assuming an ideal dipole rather than a solenoid. I have been told that this is an okay approximation, but only from farther distances away, but from farther away, the magnetic flux is almost nothing, and a distance measurement must be extremely accurate for real results (there is a r^3 sensitivity, with r measured in meters).

It has been suggested that I hang the torque rod by a very long string, measure the angle between it and the Earth's field, and attach a force meter at one end of the torque rod. Turning on the torque rod would register some force, and from that a moment could be backed out. The only problem with this method is that the actual force exerted is extremely small (something like 0.3 grams). It is feasible, but the setup would take some time, and may not be any more accurate than the gaussmeter tests.

I was wondering if anyone had any better suggestions for figuring out the magnetic moment generated by this torque rod, by any method of observation?

Thank You

 

[LightHero]

!You could use an AC bridge to measure the inductance of your torque rod. Since you know the number of turns and the diameter, you can calculate the total magnetic moment from the measured inductance. You can also use a hall effect device to measure the magnetic field strength directly. This should give you an accurate measure of the torque rod's magnetic moment.

 

[astrokreng]

As a fellow scientist, I understand the challenge you are facing in measuring the magnetic moment of your torque rod. It is important to have accurate measurements in order to ensure your torque rod meets the required specifications for your spacecraft.

One suggestion I have is to use a more advanced and precise magnetic flux density meter, also known as a teslameter. This device can measure the magnetic field with higher accuracy and can provide more reliable results for your calculations. Additionally, you may want to consider using a Hall effect sensor, which can directly measure the magnetic field and can eliminate the need for distance measurements.

Another approach could be to use a magnetometer, which can measure the Earth's magnetic field and then compare it to the magnetic field generated by your torque rod. This can help in determining the magnetic moment of your torque rod.

I also suggest consulting with experts in the field of magnetism or seeking out specialized equipment or facilities that can provide more accurate measurements for your torque rod.

In any case, it is important to carefully consider the limitations and uncertainties of any measurement method and to make sure your setup is properly calibrated and controlled for accurate results. Good luck with your research!