Hi there.
I am a mechanical engineer and am just starting to get into the world of magnetism which is both fascinating and confusing to me. Essentially I'm trying to understand what is happening in the second quadrant in a BH curve with no external field applied.
I have attached a BH curve and applied a load line for a permeance co-eff of 1.0. I believe this tells me that the the flux density of this magnetic material at 20°C is 5.75kG and roughly 4.75kG at 200°C. Am I right so far?
then projecting vertically down I get a value for H. This is what I'm not sure about. I think I understand about the coercive force etc during the magnetisation process but I am interested in the magnets properties after it has been magnetised - i.e. no external field.
Upon reading "Magnet Materials: fundamentals and device applications" by Nicola Spadin (page 128) I am left thinking that this demagnitization of 5.75kOe is due to a quantity of the flux passing back through the magnet rather than the air surrounding it. This makes sense in as much that and infinately long magnet has infinate permeance and therforeB=Br.
This further confuses me however, because I dont know the strength of the magnet? Or is this not the purpose of the curve?
Any help in clearing this misunderstanding up would be much appreciated.
I am a mechanical engineer and am just starting to get into the world of magnetism which is both fascinating and confusing to me. Essentially I'm trying to understand what is happening in the second quadrant in a BH curve with no external field applied.
I have attached a BH curve and applied a load line for a permeance co-eff of 1.0. I believe this tells me that the the flux density of this magnetic material at 20°C is 5.75kG and roughly 4.75kG at 200°C. Am I right so far?
then projecting vertically down I get a value for H. This is what I'm not sure about. I think I understand about the coercive force etc during the magnetisation process but I am interested in the magnets properties after it has been magnetised - i.e. no external field.
Upon reading "Magnet Materials: fundamentals and device applications" by Nicola Spadin (page 128) I am left thinking that this demagnitization of 5.75kOe is due to a quantity of the flux passing back through the magnet rather than the air surrounding it. This makes sense in as much that and infinately long magnet has infinate permeance and therforeB=Br.
This further confuses me however, because I dont know the strength of the magnet? Or is this not the purpose of the curve?
Any help in clearing this misunderstanding up would be much appreciated.