Electromagnetic force in electric motor

In summary, the conversation discusses the relationship between electric current density, magnetic flux density, and the materials used in a DC motor with a groove rotor. It is explained that the high magnetic reluctance of the groove materials allows the B field to enter the groove, making it more effective for the motor. The relevance of a colorful animation is also questioned.
  • #1
batsan
9
0
Suppose we have a DC motor with permanent magnet. Moreover, the armature of motor is groove rotor. The elementary electromagnetic force is given by: dF=jxBdv, where j is electric current density , x is vector multiplication , B - magnetic flux density , dv - elementary volume. If we integrate by all the volume, we will calculate only zero, because there is current density j in the groove , but there is no magnetic field B. Otherwise ,there is B in the steel , but no j.
How you can explain that?
 
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  • #2
There is B in the groove.
 
  • #3
Are you sure?
The magnetic resistance of the groove materials, such as copper, insulation ,air etc is many times more then steel. The magnetic flux pass around the groove, but not inside it.
 
  • #4
batsan said:
Are you sure?
The magnetic resistance of the groove materials, such as copper, insulation ,air etc is many times more then steel. The magnetic flux pass around the groove, but not inside it.
The hig magnetic reluctance (not resistance) of those materials is what permits the B field to enter the groove. That is why steel is not used for the armature.
 
  • #5
Ok. Is this correct picture or not?
http://www.mfly.de/animation_b.gif [Broken]
 
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  • #6
The picture is colorful, but I don't think it is relevant to your question or my answer.
 
  • #7
Yes,this is AC motor, but formula for its force must be the same. As we see color of groove is blue and it corresponds to B=0.
 
  • #8
The picture is colorful, but I don't think it is relevant to your question or my answer, since B is not zero in the groove however they color it.
 

1. What is electromagnetic force in an electric motor?

The electromagnetic force in an electric motor is the force that is generated by the interaction between the electric and magnetic fields in the motor. It is responsible for the rotation of the motor's rotor, which drives the mechanical motion.

2. How does electromagnetic force work in an electric motor?

The electromagnetic force works in an electric motor through the principle of electromagnetism. When an electric current flows through a wire, it creates a magnetic field, and when this wire is placed in a magnetic field, it experiences a force. This force is what causes the rotor of the motor to rotate.

3. What factors affect the strength of electromagnetic force in an electric motor?

The strength of the electromagnetic force in an electric motor depends on several factors, including the strength of the magnetic field, the amount of electric current flowing through the wire, and the distance between the wire and the magnetic field. Other factors such as the shape and size of the motor can also affect the force.

4. How is electromagnetic force controlled in an electric motor?

The electromagnetic force in an electric motor is controlled by varying the strength of the magnetic field or the amount of electric current flowing through the wire. This can be achieved by using different materials for the magnets, adjusting the number of turns in the wire, or using an external power source to control the current.

5. What are the applications of electromagnetic force in electric motors?

The applications of electromagnetic force in electric motors are vast, as they are used in various industries and devices. Electric motors are commonly used in household appliances, transportation, manufacturing, and many other applications. They are essential for converting electrical energy into mechanical energy, making them a crucial component in modern technology.

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