Current , Heat & Resistance

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.