Measuring AC magnetic permeability by induced electromotive force;

This article discusses the transformatoin of induced electromotive force under the condition of relativistic transformatoin, the motion－produced electromotive force do not transfer into induction－produced eletromotive force according to difference of choices of reference system.

Using the slider to drive a metal bar to cut perpendicularly the uniform magnetic field in the center of a Helmholtz coil,induction electromotive force could be produced.

The first discussion is that induced electromotive force plus moving induced electromotive force equaling induction electromotive force in experimental result ; The second discussion is that moving induced electromotive force is divided into three types, according to the generating cause of moving induced electromotive force.

On the Induced EMF in Moving System;

Induced EMF and Motional EMF are two parts of induced EMF produced in the recireulating loop of conductor.

The voltage drop thus obtained is to be divided by the number of turns of the secondary coil in order to find out the induced emf per turn.

For exploring the electromagnetic method of measuring the in-service stress of steel beams,an experiment of the relation between induction EMF E and tensile or compressive stress σ from bending was conducted for Q235B hot rolling H-section steel beam.