Fam W Z, Mikhail E L
Department of Electrical Engineering, Technical University of Nova Scotia, Halifax, Canada.
IEEE Trans Biomed Eng. 1993 Jul;40(7):708-11. doi: 10.1109/10.237701.
This paper describes a versatile exposure system which can be used to investigate the effects of a 60-Hz alternating magnetic field or traveling magnetic field on small laboratory animals. The system was designed and built as part of an extensive experimental effort to find out what effects, if any, these fields would have on the various biological systems of animals. Special attention was given to the design of the electric circuit to simplify the supply requirements and to keep the overall current to a minimum. Magnetic field having a flux density up to 30 mT (300 G) can be generated, and a traveling magnetic field is obtained by reconnecting the coils to a three-phase supply. The total magnetic field due to the currents in the three coils used in the exposure system is analyzed by considering the x, y, and z components of the flux density due to each coil, and then using the method of superposition to obtain the flux density B at any point in the region of the three coils. A computer program was written to evaluate the magnetic field in the region where the animals are located. The computed values are also compared with those obtained from actual measurements. The difference between the measured and the computed values of the flux density is attributed to the idealized representation of the multiturn, multilayer coils by equivalent single-turn coils.
