Very interesting video that shows us Guy, where we can see the correct way to measure magnetic plates and bars. Quantum Representative in Chile for Goudsmit
If there is a copper coil energized by an AC voltage, will this system be able to measure? Or just for static magnetic fields. Instead of time varying magnetic fields?
Most Gauss/Tesla meters can also measure alternating magnet fields in the lower frequency range (up to several kHz). Check the specification of a specific device if it is capable to do so. The meter used in the video can measure alternating fields with a frequency up to 5000 Hz.
Is it possible to measure the magnetic field given off by a Capacitor Discharge welding machine. Essentially, I would like to acquire values of magnetic field strength at certain distances away from this welding procedure to establish a safe boundary. I do not think I can use a probe. Any thoughts? Thanks, Nic
For measuring the magnetic field strength a magnitude gaussmeter (that measures the flux density in x, y and z direction) would be handy (see www.goudsmitmagnets.com/industrial-magnetic-systems/accessories/magnetic-field-meters/gauss-meter-teslameter). For dealing with the electric pulse of short duration it should be one that can measure in peak mode to capture the true maximum value. Probably, a measuring device can't do both. Alternatively, if you would know or can estimate the current density, you could opt to calculate the magnetic field created due to the large current flowing.
Sir, very interesting, thank you. And... if you ever stop working in the magnet industry, I'm sure you would be very successful as a Roger Daltrey impersonator!
Thank You so much for the clear explanation! It’s helped me a lot! We recently bought the same device, but I haven't understood yet how can we transfer the data to the PC. Is there any software that came with the device? I would like to know how to register the data.
Thank you for your question. The device has two USB modes: If it is set to KEYBOARD mode it will behave like a keyboard (HID human interface device) and when de DATA button is pressed, it will write the current measurement value to where ever the cursor is placed at the moment on the PC. No software is needed. In SERIAL mode you can send SCPI protocol commands (see the manual) to the device over a serial interface. This allows more elaborate programming and automation. The SCPI (Standard Commands for Programmable Instruments) protocol is used by many measurement devices. However, no separate program is supplied with the device for use in serial mode. However most ordinary programming languages can be used to implement this. Most data acquisition software will also support SCPI over USB. I would recommend using Python in Jupyter Lab, but that is my personal preference. Any programming language will do.
Nice video but in same magnet first measuring average 4,6 kG but after put a part next measuring 2,39 kG.Which is correct value. Another question,If I want measure a transformer core(CRGO) can I measure in same methot or I must apply voltage to transformer? Thank you for great tricks
If you look carefully you see my colleague first performing a measurement on the top surface of the block magnet itself. In the second measurement he applies a spacer block to measure the magnetic flux density at a distance from the surface and therefore measures a lower value. Both values are correct, but the measured values are dependent on location where they are measured. Closer to the surface the flux density is higher. Because of the configuration of magnets inside the block magnet the magnetic field lines will be most concentrated at specific points and that is at the edges of the internal magnets close to the surface. This is because two counteracting effects are at play: 1) magnetic field lines strive for maintaining the most distance to other field lines while 2) magnetic field lines seek the path of least resistance. This is the shortest path or the path through materials with the highest magnetic permeability. (which is the equivalent of conductance of a conductor in the analogy of an electric circuit). These are counteracting effects and the equilibrium that is found between them shapes the magnetic field around magnetic circuits and also results in the very localized spot near the surface where the highest flux density is found. Because of effect 1 the magnetic field lines will become less concentrated at a distance from the hotspots. That’s why at a distance the measured value will be lower. The useful magnetic flux in a transformer core is inside the material itself and therefore cannot be measured in the same way. To be able to stick a gauss meter probe in the core a gap or cutout would have to be created. Such a gap would create a large resistance for the magnetic field, which either the magnetic flux would travel around (and you would measure a lower value) or would reduce the performance of the transformer. So you can’t measure the flux density in a magnetic core in the same way as surface flux density is measured on the magnet plate.
To detect any degradation of the magnets, we usually recommend inspection once a year. Apart from checks for wear of the bullet magnet itself by abrasive media, the internal magnets themselves can only lose their magnetic strength through exposure to high temperatures, excessive impacts and external magnetic fields. Depending on the conditions of use and requirements for a specific product or by customer demand, the inspection interval could be shorter or longer than the recommended one year. For more information or help with inspections, please contact our service department: service@goudsmit.eu
It depends on what you want to measure. If you just want to determine the direction of the magnetic field, you can use a simple compass. If you want to measure the magnitude of the magnetic field, you need a Gaussmeter that has sufficient resolution to measure at that low field strength, so you will get an accurate reading. Most normal Gaussmeters will be suited for this task. A magnetic field has a magnitude but also a direction. The direction is defined as positive in the direction of the geographic north pole (which is, to complicate things, a magnetic south pole). Hold the Gaussmeter probe up vertically and rotate it around the vertical axis. The largest positive value you measure is the local magnetic field strength and that should be in the south-north direction. But there is one catch. Some rocks contain a lot of iron and that can make the earth’s magnetic field lines deviate from being perfectly horizontal. If this is the case, for example if you are in the mountains, you can measure a larger value when you tilt the probe a little bit up or down from vertical. You could also use a compass the find out if the local field direction and measure the field strength in that direction.
Thank you for this video! Very educational and useful. Can I ask, do you need different gauss/milligauss meters for permanent magnets vs electromagnetic fields? Example, can I use your type of gaussmeter for measuring magnetix flux coming from a plasma ball? Thanks
Dear Richard, In both cases the magnetic field is the result of charges that are moving. In magnets this is caused by unpaired electrons on the atomic level and in the plasma ball it are charged particles that are moving. A gauss or tesla meter can measure those fields, but because of the constantly changing magnitude and direction of the local magnetic field near a plasma ball, I don't expect a normal gauss meter (one that measures the magnetic flux in just one direction) to be very well suited for this task.
Here is a linguistic question: Gaussmeter = Teslameter (The difference lie in unit) A Gaussmeter measures the “surface magnetic flux density”. Am I correct? I work for a Chinese neodymium magnet manufacturer.
Dear JonahJin, we have both a 1D gauss meter (measurement on a surface, measures the flux density in one direction) , and 3D gauss meter (measure magnetic fields in a free space, in three directions x, y and z). For all details and products, see our website: www.goudsmitmagnets.com/solutions/accessories/magnetic-field-meters/gauss-meter-teslameter
The intrinsic magnetic properties of magnetic materials cannot be determined by measuring surface flux densities. To determine the BHmax, Br and Jhc values a BH curve must be determined for the material using a permagraph device (for more info: www.goudsmitmagnets.com/solutions/high-tech-custom-magnetic-assemblies/measuring-and-validating/permagraph.html). This is basically steel yoke with very low reluctance (‘magnetic resistance’) in which a sample of a magnetic material can be placed. The yoke and magnet form a magnetic circuit without any air gaps. Air gaps would introduce a large (unwanted) magnetic resistance in the circuit. Using a coil a powerful external magnetic field (H) can be applied on the magnet. This magnetic field induces a magnetic flux (B) in the magnet. First the field is applied in one direction until the magnet sample is fully magnetized and then the direction of the applied magnetic field is reversed and the magnet gets magnetized in the other direction. This process can be repeated. If you measure the applied field (H) and the induced magnetic flux (B) and you plot the values while repeatedly fully magnetizing the magnet in one and then the other direction a hysteresis curve will plotted. The BHmax, Br and Jhc values are determined by looking a specific points on the graph. Br, the residual magnetism, is the crossing of the B axis. Hci, the intrinsic coercive force, is the ‘knee of the curve’. BHmax is the point where the product of the values of B and H is the maximum.
It looks to me that there is a very large discrepancy between the readings that your meter gave and what the supplier had indicated. Can you please explain the reason for this.
@@GoudsmitMagnetics Thank you, after re-watching the video it seems that I must have completely missed your opening statements and somehow got caught up in the form that you showed toward the end. Now that I look I see that the form had little if anything to do with the magnets you were measuring. The impetus for the question in the first place was that I recently purchase 2 magnets that were rated by the seller as N52. I have serious doubts to the validity of this rating as the pull force and other factors indicate a much lower rating. I do not own a Gauss Meter but I am thinking of purchasing one for the sole purpose of resolving the discrepancy between the sellers claim and my observations. Again thank you. I believe you have answered all my questions.
There could be several reasons why a magnetic flux density measurement is below the expected or real value: 1) Every point in a magnetic field has a local flux density magnitude but also a direction. If the probe of the meter is not perfectly perpendicular to the local field direction you will not measure the full magnitude at that point. 2) Many magnet systems have a high surface flux density that drops of very rapidly when the distance to the surface increases. The Hall sensor used in the Tesla meter probe is ideally positioned at the surface of the probe, but in practice this is never the case. When the effective sensor depth is larger you will measure a much lower value because you measure the flux density further away from the surface. That is why surface flux densities measured will differ between two perfectly calibrated meters if the sensor depths in the probes are not exactly the same. 3) One of the properties of permanent magnetic materials is the remanence or Br value. Some people expect to be able to measure this value using a Tesla meter. This is not the case. In analogy with an electric circuit the remanence can be compared to the short circuit current that goes through an electric circuit with very low electrical resistance. This is not the same current that will flow through the same circuit with a larger resistance. In practice the reluctance (‘magnetic resistance’) of the magnetic circuits is often high due to the presence of air gaps, which have a high resistance, this results in flux densities measured that are lower than the remanence of the magnetic material used.
Dear Jake, in comparison: the magnitude of the Earth’s magnetic field ranges from 0.25 to 0.65 gauss at the surface. Therefore 10 mG (0.010 G) is only a small fraction of the Earth’s magnetic field strength. So when you consider the Earth’s magnetic field as weak then this his is even 25 to 65 times weaker. When you measure the Earth’s magnetic field in east-west direction, in which it has a zero field component, and you tilt the probe a 1-2 degrees off axis you should be able to measure a field of about 10 mG. Field strengths in the mG range can be measured accurately with a special gaussmeter or miligauss meter that has enough accuracy and resolution in that range. Most normal gaussmeters are not well suited for this.
This is our gaussmeter type HG09 (article nr. 65.0000047). You can find it on our website: www.goudsmitmagnets.com/industrial-magnetic-systems/accessories/magnetic-field-meters/gauss-meter-teslameter
Dear Goudsmit Magnetics Can you please explain the name and the material of the Protector/Measuring Tube (the one that held by left hand of the Person in Video at minute 06:38)? Do you also sell it?
Yes we sell these magnetic testing/inspection rods. See our website at: www.goudsmitmagnets.com/solutions/accessories/magnetic-inspection-rods.html?sku=SESX015048 The material of the tube is stainless steel. This material behaves like air for magnetic fields and will therefore not influence the measurement. The extra device (white) used is only to position the magnet bar in the center of the outer tube, so the measurement becomes repeatable around the circumference of the tube. You could use 3D printing to create your own end plugs for this purpose. Or contact us at www.goudsmitmagnets.com/contact/contact-form to see if we can help you.
If you mean kG (kilogauss) it is just 1000 gauss. 1 T (tesla) = 10,000 gauss = 10 kG Formally gauss and tesla are both units of magnetic flux density. Magnetic field strength is expressed in units A/m or Oe.
In a magnetic field every point in space has a magnitude of flux density but also a direction. Therefore around an energized coil there is no one single value that can be measured. Normal (1D) gauss meters just measure the magnetic flux in one direction. The value of the magnetic flux density around a coil in air is dependent on the position where it’s measured and the local direction of the magnetic field. The highest values will always be measured perpendicular to the field lines. You will measure no flux density if you position the probe along the field lines. If the coil is relatively long, the flux density inside the coil, measured perpendicularly to its axis, will be more or less constant along this axis. This is where the highest values will be measured. In practice for many coils, like those in transformers, the magnetic flux will travel through steel and you can’t position the tip of a gauss meter probe inside the material. Outside such devices you will only measure some very small stray fields. In those cases the flux density is calculated from the number of turns of the coil, the current and the permeability (‘conductivity’ of the material for magnetic flux) of the material and length and cross-section of the path that the magnetic flux travels around.
There are several methods to do this. Basically what you do is to compare the measurement made by the device to be calibrated with a precisely known reference value. If the value is replicated within the accuracy range of the Gauss meter it passes the calibration. One method to do this is to use so called calibration magnets as a reference. A calibration magnet is a magnetic circuit with a narrow gap in which a homogenous magnetic field is present. Homogenous means the magnetic flux density is not dependent on the position in the gap. The probe of the gauss meter can therefore move around and will still measure the same value everywhere. The value of the magnetic flux density in the gap of the calibration magnet is known with a higher accuracy than the accuracy of the gauss meter itself so you can make an accurate comparison. For more information or contact, please visit our website on www.goudsmitmagnets.com
That was a very concise and clear to understand video. Thank you for taking the time to do it. I enjoyed and learned a lot!
Very interesting video that shows us Guy, where we can see the correct way to measure magnetic plates and bars. Quantum Representative in Chile for Goudsmit
If there is a copper coil energized by an AC voltage, will this system be able to measure? Or just for static magnetic fields. Instead of time varying magnetic fields?
Most Gauss/Tesla meters can also measure alternating magnet fields in the lower frequency range (up to several kHz). Check the specification of a specific device if it is capable to do so. The meter used in the video can measure alternating fields with a frequency up to 5000 Hz.
Is it possible to measure the magnetic field given off by a Capacitor Discharge welding machine. Essentially, I would like to acquire values of magnetic field strength at certain distances away from this welding procedure to establish a safe boundary.
I do not think I can use a probe. Any thoughts?
Thanks,
Nic
For measuring the magnetic field strength a magnitude gaussmeter (that measures the flux density in x, y and z direction) would be handy (see www.goudsmitmagnets.com/industrial-magnetic-systems/accessories/magnetic-field-meters/gauss-meter-teslameter).
For dealing with the electric pulse of short duration it should be one that can measure in peak mode to capture the true maximum value. Probably, a measuring device can't do both. Alternatively, if you would know or can estimate the current density, you could opt to calculate the magnetic field created due to the large current flowing.
Very interesting but i have a question: there is one international norm for this kinde of misure?
Hello. No, unfortunately there's no standard for this specific measurement.
Sir, very interesting, thank you. And... if you ever stop working in the magnet industry, I'm sure you would be very successful as a Roger Daltrey impersonator!
Thank You so much for the clear explanation!
It’s helped me a lot! We recently bought the same device, but I haven't understood yet how can we transfer the data to the PC. Is there any software that came with the device? I would like to know how to register the data.
Thank you for your question.
The device has two USB modes:
If it is set to KEYBOARD mode it will behave like a keyboard (HID human interface device) and when de DATA button is pressed, it will write the current measurement value to where ever the cursor is placed at the moment on the PC. No software is needed.
In SERIAL mode you can send SCPI protocol commands (see the manual) to the device over a serial interface. This allows more elaborate programming and automation. The SCPI (Standard Commands for Programmable Instruments) protocol is used by many measurement devices.
However, no separate program is supplied with the device for use in serial mode. However most ordinary programming languages can be used to implement this. Most data acquisition software will also support SCPI over USB. I would recommend using Python in Jupyter Lab, but that is my personal preference. Any programming language will do.
Nice video but in same magnet first measuring average 4,6 kG but after put a part next measuring 2,39 kG.Which is correct value.
Another question,If I want measure a transformer core(CRGO) can I measure in same methot or I must apply voltage to transformer?
Thank you for great tricks
If you look carefully you see my colleague first performing a measurement on the top surface of the block magnet itself. In the second measurement he applies a spacer block to measure the magnetic flux density at a distance from the surface and therefore measures a lower value. Both values are correct, but the measured values are dependent on location where they are measured. Closer to the surface the flux density is higher.
Because of the configuration of magnets inside the block magnet the magnetic field lines will be most concentrated at specific points and that is at the edges of the internal magnets close to the surface. This is because two counteracting effects are at play:
1) magnetic field lines strive for maintaining the most distance to other field lines while
2) magnetic field lines seek the path of least resistance. This is the shortest path or the path through materials with the highest magnetic permeability. (which is the equivalent of conductance of a conductor in the analogy of an electric circuit).
These are counteracting effects and the equilibrium that is found between them shapes the magnetic field around magnetic circuits and also results in the very localized spot near the surface where the highest flux density is found. Because of effect 1 the magnetic field lines will become less concentrated at a distance from the hotspots. That’s why at a distance the measured value will be lower.
The useful magnetic flux in a transformer core is inside the material itself and therefore cannot be measured in the same way. To be able to stick a gauss meter probe in the core a gap or cutout would have to be created. Such a gap would create a large resistance for the magnetic field, which either the magnetic flux would travel around (and you would measure a lower value) or would reduce the performance of the transformer. So you can’t measure the flux density in a magnetic core in the same way as surface flux density is measured on the magnet plate.
@@GoudsmitMagneticswhat is the material of spacer block?
@@alfita6803This one is made of plastic, but any non-magnetic material would do.
How often i need to check my bullet magnet? please recommend
To detect any degradation of the magnets, we usually recommend inspection once a year.
Apart from checks for wear of the bullet magnet itself by abrasive media, the internal magnets themselves can only lose their magnetic strength through exposure to high temperatures, excessive impacts and external magnetic fields.
Depending on the conditions of use and requirements for a specific product or by customer demand, the inspection interval could be shorter or longer than the recommended one year. For more information or help with inspections, please contact our service department: service@goudsmit.eu
What device to measure magnetic field on certain place ???,on the mountain for example
It depends on what you want to measure. If you just want to determine the direction of the magnetic field, you can use a simple compass.
If you want to measure the magnitude of the magnetic field, you need a Gaussmeter that has sufficient resolution to measure at that low field strength, so you will get an accurate reading. Most normal Gaussmeters will be suited for this task.
A magnetic field has a magnitude but also a direction. The direction is defined as positive in the direction of the geographic north pole (which is, to complicate things, a magnetic south pole). Hold the Gaussmeter probe up vertically and rotate it around the vertical axis. The largest positive value you measure is the local magnetic field strength and that should be in the south-north direction.
But there is one catch. Some rocks contain a lot of iron and that can make the earth’s magnetic field lines deviate from being perfectly horizontal. If this is the case, for example if you are in the mountains, you can measure a larger value when you tilt the probe a little bit up or down from vertical. You could also use a compass the find out if the local field direction and measure the field strength in that direction.
Thank you for this video! Very educational and useful.
Can I ask, do you need different gauss/milligauss meters for permanent magnets vs electromagnetic fields?
Example, can I use your type of gaussmeter for measuring magnetix flux coming from a plasma ball? Thanks
Dear Richard, In both cases the magnetic field is the result of charges that are moving. In magnets this is caused by unpaired electrons on the atomic level and in the plasma ball it are charged particles that are moving. A gauss or tesla meter can measure those fields, but because of the constantly changing magnitude and direction of the local magnetic field near a plasma ball, I don't expect a normal gauss meter (one that measures the magnetic flux in just one direction) to be very well suited for this task.
Here is a linguistic question:
Gaussmeter = Teslameter
(The difference lie in unit)
A Gaussmeter measures the “surface magnetic flux density”.
Am I correct? I work for a Chinese neodymium magnet manufacturer.
@@GoudsmitMagnetics Thank you for your quick reply. I remember there is a magnetic flux meter in our lab that is produced by a german company
Dear JonahJin, we have both a 1D gauss meter (measurement on a surface, measures the flux density in one direction) , and 3D gauss meter (measure magnetic fields in a free space, in three directions x, y and z).
For all details and products, see our website: www.goudsmitmagnets.com/solutions/accessories/magnetic-field-meters/gauss-meter-teslameter
Sir can you please let me know how to find BHmax, Br and JHc of a magnet. Is it calculated after measuring the KG of a magnet ???
The intrinsic magnetic properties of magnetic materials cannot be determined by measuring surface flux densities. To determine the BHmax, Br and Jhc values a BH curve must be determined for the material using a permagraph device (for more info: www.goudsmitmagnets.com/solutions/high-tech-custom-magnetic-assemblies/measuring-and-validating/permagraph.html). This is basically steel yoke with very low reluctance (‘magnetic resistance’) in which a sample of a magnetic material can be placed. The yoke and magnet form a magnetic circuit without any air gaps. Air gaps would introduce a large (unwanted) magnetic resistance in the circuit. Using a coil a powerful external magnetic field (H) can be applied on the magnet. This magnetic field induces a magnetic flux (B) in the magnet. First the field is applied in one direction until the magnet sample is fully magnetized and then the direction of the applied magnetic field is reversed and the magnet gets magnetized in the other direction. This process can be repeated.
If you measure the applied field (H) and the induced magnetic flux (B) and you plot the values while repeatedly fully magnetizing the magnet in one and then the other direction a hysteresis curve will plotted. The BHmax, Br and Jhc values are determined by looking a specific points on the graph.
Br, the residual magnetism, is the crossing of the B axis. Hci, the intrinsic coercive force, is the ‘knee of the curve’. BHmax is the point where the product of the values of B and H is the maximum.
thank you for this valuable information
It looks to me that there is a very large discrepancy between the readings that your
meter gave and what the supplier had indicated. Can you please explain the reason
for this.
@@GoudsmitMagnetics
Thank you, after re-watching the video it seems that I must have completely missed your opening statements and somehow got caught up in the form that you showed toward the end. Now that I look I see that the form had little if anything to do with the magnets you were measuring. The impetus for the question in the first place was that I recently purchase 2 magnets that were rated by the seller as N52. I have serious doubts to the validity of this rating as the pull force and other factors indicate a much lower rating. I do not own a Gauss Meter but I am thinking of purchasing one for the sole purpose of resolving the discrepancy between the sellers claim and my observations.
Again thank you. I believe you have answered all my questions.
There could be several reasons why a magnetic flux density measurement is below the expected or real value:
1) Every point in a magnetic field has a local flux density magnitude but also a direction. If the probe of the meter is not perfectly perpendicular to the local field direction you will not measure the full magnitude at that point.
2) Many magnet systems have a high surface flux density that drops of very rapidly when the distance to the surface increases. The Hall sensor used in the Tesla meter probe is ideally positioned at the surface of the probe, but in practice this is never the case. When the effective sensor depth is larger you will measure a much lower value because you measure the flux density further away from the surface. That is why surface flux densities measured will differ between two perfectly calibrated meters if the sensor depths in the probes are not exactly the same.
3) One of the properties of permanent magnetic materials is the remanence or Br value. Some people expect to be able to measure this value using a Tesla meter. This is not the case. In analogy with an electric circuit the remanence can be compared to the short circuit current that goes through an electric circuit with very low electrical resistance. This is not the same current that will flow through the same circuit with a larger resistance. In practice the reluctance (‘magnetic resistance’) of the magnetic circuits is often high due to the presence of air gaps, which have a high resistance, this results in flux densities measured that are lower than the remanence of the magnetic material used.
How we can detect mmf from distance meter
How much is 10 milligauss? Is this a lot? Could this easily be detected on Earth within about 5-10 feet above Earth's surface?
Dear Jake, in comparison: the magnitude of the Earth’s magnetic field ranges from 0.25 to 0.65 gauss at the surface. Therefore 10 mG (0.010 G) is only a small fraction of the Earth’s magnetic field strength. So when you consider the Earth’s magnetic field as weak then this his is even 25 to 65 times weaker.
When you measure the Earth’s magnetic field in east-west direction, in which it has a zero field component, and you tilt the probe a 1-2 degrees off axis you should be able to measure a field of about 10 mG. Field strengths in the mG range can be measured accurately with a special gaussmeter or miligauss meter that has enough accuracy and resolution in that range. Most normal gaussmeters are not well suited for this.
What is the type of the gauss meter in the video
This is our gaussmeter type HG09 (article nr. 65.0000047). You can find it on our website: www.goudsmitmagnets.com/industrial-magnetic-systems/accessories/magnetic-field-meters/gauss-meter-teslameter
Dear Goudsmit Magnetics
Can you please explain the name and the material of the Protector/Measuring Tube (the one that held by left hand of the Person in Video at minute 06:38)? Do you also sell it?
Yes we sell these magnetic testing/inspection rods. See our website at: www.goudsmitmagnets.com/solutions/accessories/magnetic-inspection-rods.html?sku=SESX015048
The material of the tube is stainless steel. This material behaves like air for magnetic fields and will therefore not influence the measurement. The extra device (white) used is only to position the magnet bar in the center of the outer tube, so the measurement becomes repeatable around the circumference of the tube. You could use 3D printing to create your own end plugs for this purpose. Or contact us at www.goudsmitmagnets.com/contact/contact-form to see if we can help you.
How can you measuring the magnetic field with Kg units??
If you mean kG (kilogauss) it is just 1000 gauss. 1 T (tesla) = 10,000 gauss = 10 kG
Formally gauss and tesla are both units of magnetic flux density. Magnetic field strength is expressed in units A/m or Oe.
IF WE MEASURE ANY COIL MAGNET THAN HOW WE DO IT?
In a magnetic field every point in space has a magnitude of flux density but also a direction. Therefore around an energized coil there is no one single value that can be measured.
Normal (1D) gauss meters just measure the magnetic flux in one direction. The value of the magnetic flux density around a coil in air is dependent on the position where it’s measured and the local direction of the magnetic field. The highest values will always be measured perpendicular to the field lines. You will measure no flux density if you position the probe along the field lines.
If the coil is relatively long, the flux density inside the coil, measured perpendicularly to its axis, will be more or less constant along this axis. This is where the highest values will be measured.
In practice for many coils, like those in transformers, the magnetic flux will travel through steel and you can’t position the tip of a gauss meter probe inside the material. Outside such devices you will only measure some very small stray fields. In those cases the flux density is calculated from the number of turns of the coil, the current and the permeability (‘conductivity’ of the material for magnetic flux) of the material and length and cross-section of the path that the magnetic flux travels around.
How to calibrate the gauss meter ?
There are several methods to do this. Basically what you do is to compare the measurement made by the device to be calibrated with a precisely known reference value. If the value is replicated within the accuracy range of the Gauss meter it passes the calibration.
One method to do this is to use so called calibration magnets as a reference. A calibration magnet is a magnetic circuit with a narrow gap in which a homogenous magnetic field is present. Homogenous means the magnetic flux density is not dependent on the position in the gap. The probe of the gauss meter can therefore move around and will still measure the same value everywhere.
The value of the magnetic flux density in the gap of the calibration magnet is known with a higher accuracy than the accuracy of the gauss meter itself so you can make an accurate comparison.
For more information or contact, please visit our website on www.goudsmitmagnets.com
Thank you for the knowledge sir.
very informative
big one is table so careful
Nice