Measurement of hysteresis curve of permanent magnetic samples - locating sample between pole pieces electromagnet with voltages induced in inset coils giving voltages proportional to flux density and field strength

摘要

A magnetic yoke (10) has a `U' shaped form and has pole pieces (11, 12). An excitation coil (13) is mounted on the yoke and a gap (14) exists between the pole pieces and coils are inset (14, 16) that measure induction voltages (Ub, UH). A permanent magnetic sample (17) is inserted into the `B' coil (15) for measurement of the hystersis characteristic. The polarisation value, I, is given by the relationship I = B + Mo.H = (1/AW) integral of (UB+UH) dt + Io, where A and W are the coil sizes. The voltage values are received by a processor (18) for the equation to be evaluated. ADVANTAGE - Improved measurement accuracy.