Correct Answer - Option 4 : Arc heating
This type of electric heating can be categorized as
- Induction Heating
- Dielectric Heating
- Infrared Heating
So, Arc heating is not considered as high-frequency heating as it is conducted at Power frequency.
- This is the most inefficient method of electric heating. It is also the simplest form of electric heating.
- Here the electromagnetic radiation coming out from an incandescent light bulb is focused to the surface to be heated.
- It is mostly used for drying out the wet painted surface of an object.
- It is very difficult to uniformly heat up an installation material like wood, ceramic, and plastic, etc.
- Here high frequency dielectric capacitive heating is employed.
- Dielectric material connected between two electrodes behaves as a capacitor, and high-frequency current can pass through the capacitor.
- The current through the capacitor causes uniform heating in the dielectric material. The frequency applied in dielectric heating is very high in the range of 10 to 50 kHz, but the efficiency of this system is low about 50%.
- The current gets induced in the charge itself due to changing current nearby.
- Due to the inherent resistance of the charge, there is heat produced in the charge itself.
- Induction furnace and eddy current heater are two well-known examples of direct induction electric heating.
- The very high temperatures can be obtained from the arc.
- Arc can be formed either between two electrodes of sufficient potential difference or between one electrode and the charge itself. In the second case, the charge itself behaves like the other electrode.