Page 265 - Electrician - TT (Volume 2)

ELECTRICIAN - CITS

The above principle is used in operating the thermostat (thermal switch). The thermostat has two contact points,
namely, the fixed contact point and moveable contact point. The moveable contact of thermostat consists of
a bimetal strip which is normally in contact with another strip of metal having fixed contact. The thermostat is
connected in series with the heating element as shown in the Fig. and is fitted inside the cover of the iron above
the pressure plate.

After switching on the iron, the current starts to flow through this contact point and thus the temperature rises.
When the temperature reaches beyond a certain adjusted temperature, the contact point of the bimetal strip
opens which now stops the flow of current through the heating element. Thus the circuit of the heating element

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CITS : Power - Electrician & Wireman - Lesson 101-103