Yoshio Kano

New linear variable differential transformer with square coils

A novel long stroke linear variable differential transformer (LVDT) which gives a linear analog position detecting signal is investigated. This simple-structure LVDT consists of a core, an exciting coil, and two detecting coils, and it gives good linearity. The relationships among the width of the excitation coil, the core length, the number of cores, and the position of the detection coils were investigated. When the linear range is 90% or less of the core stroke, the detection error is 0.45% or less. >

Linear position detector with rod shape electromagnet

A no-contact, high-speed linear position detector with a very simple structure is described. The detector also has the advantages of small size and light weight. It gives a linear analog signal by a Hall cell and it can be easily attached to a device such as linear motor for precise linear positioning. Its detection characteristic is described, and its available detection range is discussed on the basis of simulation results. Its quick response ability makes the position detector suitable for detecting high-speed linear motion. >

Analysis and reformation of characteristic of linear electromagnetic solenoid

The distribution of thrust in linear electromagnetic solenoids (LESs) is exponential rather than constant with displacement. In order to make the solenoids widely useful the thrust is calculated from first principles and its distribution is reformed to be flat by changing the magnetic circuit. The magnetic flux density and thrust are calculated using the finite element method. The results are compared with the experimental results obtained from the LES. >

Variational principle in 3D magnetostatic field

It is demonstrated that in a 3-D nonlinear field the variational principle does not hold. Using a dyadic operator, a new expression is introduced in place of the curl curl operation for vector potential translation of magnetostatic field equations. The control equation, taking the gauge of the vector potential A into account, is then clarified and found to be different from the equation in the linear medium. It is shown that the equation derived from the variational principle does not agree with the control equation in the 3-D nonlinear field, so the variational principle does not hold, and Ritzs method can not be used. The variational principle in the 2-D field, is discussed. >

New vector Green theorem using dyadic operator

A vector-Green-Theorem extended form of the scalar Green theorem is introduced and is compared with the revised Stratton vector Green theorem. The potential translation of the vector Poisson equation in a multimedium magnetostatic field is discussed. It is shown that the integral form of A given by the new vector Green Formula can be connected with the boundary value problem of the vector Poisson equation, but the integral form obtained by the revised Stratton formula cannot. >