ion of electromagnet force
As? = 0.1 mm, then Maxwell s formula will be used for finding electromagnetic pulling force:
В
,
where Ф - is the magnetic flux, Wb;
Ој0 - is magnetic constant, or vacuum permeability,; - is the square of the core, m2.
4. Defining of actuation time
calculate actuation time, knowing next parameters:
В В В В В В В В
Then the average magnitude of counteracting force is to be found:
В
Then the inductance of the winding is to be found:
В
,
where??? - Is the total permeance of the electromagnet, H;
w - is the number of turns in the coil.the pick-up time of the electromagnet is to be found:
В
, L - is the inductance of winding, H; - is the resistance of the coil,?; з - is the assurance factor.lets find the mass of movable parts:
В
, V - is the volume of the armature, m3;
? st - is the density of steel, kg/m3.
Then the moving time is determined:
В
, m - is the mass of the movable parts, kg;
? п - is the value of the operating air-gap.time is equal to:
В
.
Conclusions
electromagnet is simply a coil of wire. It is usually wound around an iron core. However, it could be wound around an air core, in which case it is called a solenoid. When connected to a DC voltage or current source, the electromagnet becomes energized, creating a magnetic field just like a permanent magnet. The magnetic flux density is proportional to the magnitude of the current flowing in the wire of the electromagnet. The polarity of the electromagnet is determined by the direction the current. The north pole of the electromagnet is determined by using your right hand. Wrap your fingers around the coil in the same direction as the current is flowing (conventional current flows from + to -). The direction your thumb is pointing is the direction of the magnetic field, so north would come out of the electromagnet in the direction of your thumb. DC electromagnets are principally used to pick up or hold objects.connected to an AC voltage or current source, the electromagnet will be changing its flux density as the current fluctuates. The polarity of the magnet will also change as the current reverses direction every half cycle. AC electromagnets can be used to demagnetize objects (like TV screens, audio tapes, vcr tapes) or to hold objects. However, due to the inductance of the electromagnet, the AC current that will actually flow will be reduced when compared to a DC voltage equal to the RMS value of the AC voltage feeding the electromagnet.key importance of an electromagnet is the ability to control the strength of the magne...
