The load-lifting force of the magnetic field created by the coil with current is defined by current in a winding, quantity of rounds and also magnetic permeability of material of the core. In addition, force of an attraction of objects to a magnet is influenced by their form.
Instruction
1. Find the magnetodriving force of an electromagnet in ampere rounds. For this purpose increase current in a winding by quantity of rounds in it.
2. Divide result into the coefficient determined by a form of objects which are supposed to be attracted to an electromagnet. This coefficient is dimensionless size, and for continuous sheets is equal 1, for spheres - 0.5, and for shaving - about 0.2. As a result of multiplication the size called a magnetic flux will turn out.
3. If not the relative, but absolute magnetic permeability of material of the core expressed in henry on meter is known, divide it into absolute magnetic permeability of a vacuum (magnetic constant). It is approximately equal 1.257*10^-6 to G/m. You receive the relative magnetic permeability which is dimensionless size.
4. Square a magnetic flux then increase by relative magnetic permeability of material of the core (it has to be close to relative magnetic permeability of material of the attracted objects, otherwise the result of calculation will be inexact). Then increase result by the safety factor equal 0.5 then divide into the area of contact of the attracted objects with an electromagnet pole.
5. The load-lifting force of an electromagnet expressed in newtons will turn out. If desired it can be transferred to the maximum mass of objects of the same form and from the same material, capable to be at the same time lifted by the same electromagnet. For this purpose divide force into the acceleration of gravity equal of 9.81 m / (с^2). The result will turn out in kilograms.
6. Magnetic conductors are capable to be sated, that is, to lose ability to further magnetization if magnetic induction reaches a certain extreme value. Schedules of magnetic saturation of substances have various form. For the majority of the materials used as a part of cores of electromagnets, these schedules can be found in reference books. Consider that after saturation the further increase in current in a winding does not lead to increase in carrying power, and only causes overheating of the device.