Monday, May 16, 2016

2.3 Electromagnetic Induction

This is the third week of Module 2 of the Navy Basic Electricity and Electronics series. The last couples week were:

2.1 Electromotive Force
2.2 Magnetism

This section is about the dynamics of electromagnetic induction involving a magnetic field and a conductor moving through it.
  • The diagram below shows a magnetic field moving from the north end of one magnet into the south end of the other. A conductor is moving through the magnetic field, which generates an electric current.

  • There is a "left hand rule" for such situations (for the generation of current). [1]
  • In the left hand rule, you place your index finger pointing like a gun in the direction of the magnetic field, with your thumb pointing in the direction that the conductor is moving through the magnetic field. Then your middle finger (pointing in the third dimension) indicates the direction of the current. See the second diagram.
  • There are three ways to increase the electromagnetic force. One is to increase the strength of the magnetic field. A second is to increase the speed of the conductor as it moves through the magnetic field. The third is to increase the length of the conductor moving through the magnetic field.
  • EMF will only be generated if the conductor is moving perpendicular to the field, not if it is moving parallel to the magnetic lines of force.
Next week: 2.4 Generating AC Voltage

[1] A right hand rule is used in physics for torque and other aspects of current. In math, a right hand rule is used to find the cross-product.

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