ELECTRICAL HEATING - PART - 14 - THREE PROBLEMS IN HIGH FREQUENCY HEATING

PROBLEM – 01 – The slab material 2 cm thick and 150 square centimetre in area having relative permittivity 4 and power factor of 0.04 is to be heated using dielectric heating. The power frequency is 250 watts are a frequency of 30 MHz. Determine the voltage and the current that will flow through the material. If the voltage were to be limited to 600 V. What would be the frequency for the same power requirement?

PROBLEM – 02 – A piece of an insulating material is to be heated by dielectric heating the size of the piece is 10 x 10 x 3 cm. A frequency is 500 W. Calculate the necessary for heating and the current that follows in the material. The material has a relative permittivity of 5 and power factor of 0.05.

PROBLEM – 03 – The wooden board 30 x 15 x 2 cms is to be heated from 20 degree centigrade to 180 degree centigrade in 10 minute by dielectric heating using 50 MHz supply. Specific heat of wood is o.35 and density 0.55 gm/c.c relative permittivity is 5 and power factor is 0.05. Estimate the voltage across the specimen and current during heating. Assume loss of energy by conduction, convection and radiation as 10%.