- is the coefficient of bulging.bulging coefficient is to be found:
В
,
where?? - Is the permeance of the operating air-gap, H;
?? T - is the front magnetic flux permeance of the operating air-gap, H.
Then the pole face area is calculated
;
;
В
where B? - Is magnetic induction, T;
? вп - is the coefficient of bulging; is the diameter of the core, m.
1.5. Determination of the steel magnetic potential drops
let s find the magnetic potential drops of the magnetic circuit by the method of leakage ratio. The division of the electromagnet is shown on the Figure
1.5.1 At first the core is divided by 5 equal parts (x) equaled to
1.5.1. - Dividing of a magnetic circuit on subcircuits
Now the leakage ratios of every subcircuit must be defined:
В
where xi - is the length from the top of the core to the middle of the investigated subcircuit;
? S - is the specific permeance; in this case this is the specific permeance of coaxial cylinders:
В
. that, the total permeance??? is found:
В
;
;
,??,?? 1,?? 2 - are the permeances of the air-gaps, H., the calculations for the first subcircuit are made. The bulging coefficient? X1 is found
В
,
where? S - is the specific permeance,; in this case this is the specific permeance of coaxial cylinders;
??? - Is the total permeance, H.the magnetic flux through the first subcircuit is made:
;
, Ф? - Is the magnetic flux through the circuit, Wb;
? X1 - is the bulging coefficient of the subcircuit.
After it, the induction of the core is found:
В
, ФX1 - is the magnetic flux through the subcircuit, Wb; - is the diameter of the core, m.induction of the yoke is found:
;
.
From the graph of magnetic curves [5] the magnetic intensity is taken:
;
.
lets find magnetic potential drop of the first subcircuit:
;
.
for the next subcircuits are done by analogy to the first one.
the magnetic potential drop in the armature can be found. At first, the magnetic flux through the armature is found:
;
it, the induction of the armature is found:
В
В
From the graph of magnetic curves [5] the magnetic intensity is taken:
.
lets find magnetic potential drop:
;
.
Now the magnetic potential drop in the base of the electromagnet can be found. The parasitic air-gap can be neglected and the base can be decided to be entire, because the existence of such a little air-gap...
