Well we are very much familiar with current, voltage and
their interrelation.
I was experimenting with a dc motor and power supply. I
connected it through a speed controller. I tested at variable speeds and
observe the wire. When i run it at full speed the wire gradually got heated.
This made me think about several possibilities like: Why the
same wire is heated when the motor attains it's full speed? And
linked all the possible angles. I conclude that the reason is current. When we
switch it to full speed the load draws high amount of current but the wire does
not support the current value. So the I2R loss produce
the heat.
Basically in a conductor the current which is flowing
through is only due to the free electrons. The resistance of the wire is
depending upon the amount of free electrons. If the free electrons are less the
resistance is high. And if the free electron is more the resistance is low.
Then what is free electrons?
Free electrons are the electrons cloud which is placed at
the outer side of an atom. The electrons are distributed in the orbits revolves
around the nucleus. The attraction force near the nucleus is more and is
decreases towards outermost. “The free electrons are placed at the extreme
position of the atom which has less attraction force by the nucleus and they
can move with less amount of force. Free electrons are moving randomly, when a
potential difference is applied they arrange in a particular manner and
completes the path. They only transfer the energy.
Cause of Heating: -
According to “BOHR” the electrons are distributed in
different energy levels, when an electron gets energies it jumps to the higher
orbit. When we increase the amount of current for a particular conductor, the
free electron cloud is insufficient to transfer the energy, so that the inner
orbital electrons are absorbers the energy and excited to the free electron
cloud. This process is a continuous attraction and repulsion between nucleus
and energized electron this effect produces the heat. When further we
increasing the current the material became fused and lost its property. So this
maybe the possible reason of heating.
