Page 300 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

insulation resistance, the greater the heater’s ability to handle the voltage and operate correctly. As current travels
through the heating element, low insulation resistance can allow the voltage to arc across the dielectric material
and ground out to the sheath, which can destroy the heater or cause broader system damage.

Magnesium oxide (MgO) is typically used as a dielectric material to insulate the element wire from the heating surface
or outer sheath. As long as the insulation resistance of the MgO remains high, the heater can function correctly.
While MgO is an excellent high-temperature insulator, it also is hygroscopic, meaning that it likes water and actively
draws moisture out of the surrounding atmosphere, effectively lowering the insulation resistance. If too much
moisture is present when the heater is fully powered up, the current will find the shortest path out by arcing to the
sheath and shorting out the heater.
A heater arcing and grounding out can have a range of consequences, from a nuisance trip of a breaker to an
explosive event. Depending on the voltage and type of material being heated, a short to ground can result in a
more significant explosive event generating damage, injury or even death, so understanding how to perform a
megohm test properly is essential to safe operation.
Working Principle of Commercial Induction Cook :
Without an open fire, how does the induction cooker heat food? If the induction cooker is still like some unbelievable
scientific mystery for you, let’s find out the working principle of it together

The induction stove works on the principle of electromagnetism, which is a new thermal energy technique. The
surface of the induction stove is usually glass-ceramic, and a coil made of copper wire is installed underneath the
glass-ceramic.

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CITS : E & H - Electronics Mechanic - Lesson 160 - 179