Search results
Results From The WOW.Com Content Network
The maximum energy product is defined based on the magnetic hysteresis saturation loop (B-H curve), in the demagnetizing portion where the B and H fields are in opposition. It is defined as the maximal value of the product of B and H along this curve (actually, the maximum of the negative of the product, − BH , since they have opposing signs):
The unit was established by the IEC in the 1930s [4] in honour of Danish physicist Hans Christian Ørsted.Ørsted discovered the connection between magnetism and electric current when a magnetic field produced by a current-carrying copper bar deflected a magnetised needle during a lecture demonstration.
Maximum energy product, (BH) max Largest possible field of a rectangle on the hysteresis loop plot, which has two edges on the B and H axes, and a vertex on the hysteresis loop in the second quadrant (B positive, H negative); range from below 1 J/m 3 for some soft materials (permalloy, 3E4 ferrite), to above 400 kJ/m 3 for hard ones ( neodymium ...
The coercivity is a measure of the degree of magnetic hysteresis and therefore characterizes the lossiness of soft magnetic materials for their common applications. The saturation remanence and coercivity are figures of merit for hard magnets, although maximum energy product is also commonly quoted.
Neodymium magnets are graded according to their maximum energy product, which relates to the magnetic flux output per unit volume. Higher values indicate stronger magnets. For sintered NdFeB magnets, there is a widely recognized international classification.
A magnet's maximum energy product (BH) max, which is roughly proportional to its coercivity (H C) and magnetization saturation (M sat), is used as a metric of its ability to do magnetic work as (BH) max is twice the magnet's available magnetostatic energy. [3]
Magnetic current density, which has the unit V/m 2 (volt per square meter), is usually represented by the symbols and . [a] The superscripts indicate total and impressed magnetic current density. [1] The impressed currents are the energy sources. In many useful cases, a distribution of electric charge can be mathematically replaced by an ...
Magnetic induction B (also known as magnetic flux density) has the SI unit tesla [T or Wb/m 2]. [1] One tesla is equal to 10 4 gauss. Magnetic field drops off as the inverse cube of the distance ( 1 / distance 3 ) from a dipole source. Energy required to produce laboratory magnetic fields increases with the square of magnetic field. [2]