ELECTROMAGNET IN MAGNETIC LEVITATION TRANSPRORT
Data of reciept 11.07.2017
Decision on publication 17.07.2017
Objective. Of the work consists in receiving new analytic expressions for determination
of inductance of vehicular electromagnets of transport levitation systems.
Methods. The key feature of calculation model of onboard coils in accordance with
their inductance on the example of squared electromagnets lies an assumption about a small-
ness of the size «heights» in comparison with its other geometrical sizes. There is also an as-
sumption that thickness of a skin layer of the conductor significantly surpasses cross sectional
size of the wire making the coil. The single-turn coil is considered, inductance of an actual
electromagnet is accepted proportional to a square of the number of turns. When calculating
inductance the dimensionless quantities are used. As an absolute, a quarter of perimeter of the
coil on the centerline is chosen. The condition of obtaining the approximate formula for calcu-
lation of inductance of the flat rectangular coil is the small thickness of a winding in compari-
son with the geometrical sizes of the coil.
Results. Accurate analytical expression for inductance of a «thin» source of square-
shaped magnetic field as the algebraic sum of elementary functions has been received. Results
of a numerical analysis show dependence of the relative inductance of the square-shaped flat
coil on thickness relation to its minimum size. Influence of «elongation» of the coil (relation
of length to width) is investigated. It is noted that inductance decreases with decrease of
«elongation», and also with increase in the relation of thickness to the minimum size.
Practical importance. The approximate formula for calculation of value of inductance
has been obtained. Its uncertainty does not exceed 14 % in the areas of changes of all geomet-
rical parameters of an electromagnet is output. Borders of practical application of the received
analytic expressions at the accepted assumptions have been set.
The received expressions are fairly simple structurally and are easily programmed
Inductance of onboard electromagnets, flat coil, skin layer, numerical analysis.