Title :
A bipolar pulse-type hysteresis loop tracer for rare earth based permanent magnets
Author :
Rhee, J.R. ; Kee, Y.H. ; Kim, M.Y. ; Lee, J.M. ; Oh, M.Y. ; Hwang, G. ; Lee, S.S. ; Park, C.M.
Author_Institution :
Dept. of Phys., Sookmyung Women´´s Univ., Seoul, South Korea
fDate :
7/1/1998 12:00:00 AM
Abstract :
An user-friendly and economical hysteresis loop tracer that permits to measure four-quadrant J-H loop of Nd based high coercivity magnet is constructed. An alternate pulse magnetic field with a peak value of about 10 T is generated by a way of connecting 3 monopolar pulse generators to an air solenoid magnet by using a sequential ignition circuit and a magnet exciting circuit. The J-H loops with initial magnetization curves are then obtained for rod type Nd based magnets (length of 5 mm and diameter of 5 mm) with an electronic fluxmeter. The increase of apparent coercivity of the magnets due to the eddy current effect is calculated, considering eddy current loss by analyzing a wave of generating magnetic field. The results are calibrated with pure Ni rods with the dimension identical to the Nd magnets
Keywords :
boron alloys; coercive force; eddy current losses; iron alloys; magnetic hysteresis; magnetic variables measurement; neodymium alloys; permanent magnets; pulse generators; solenoids; 5 mm; NdFeB; air solenoid magnet; alternate pulse magnetic field; apparent coercivity; bipolar pulse-type hysteresis loop tracer; economical; eddy current effect; eddy current loss; four-quadrant J-H loop; initial magnetization curves; magnet exciting circuit; monopolar pulse generators; neodymium based high coercivity magnet; rare earth based permanent magnets; rod type magnets; sequential ignition circuit; user-friendly; Coercive force; Eddy currents; Joining processes; Magnetic circuits; Magnetic field measurement; Magnetic hysteresis; Neodymium; Pulse circuits; Pulse generation; Solenoids;
Journal_Title :
Magnetics, IEEE Transactions on
