Specifications

97
8. ELECTRICAL COOKING APPLIANCES
8.1 INTRODUCTION
An electric stove converts electricity into heat to cook and bake.
The first technology used resistive heating coils which heated iron hotplates, on top of
which the pots were placed. In the 1970s, glass-ceramic cooktops started to appear. Glass-
ceramic has very low thermal conductivity, but lets infrared radiation pass very well. Electrical
heating coils or infrared halogen lamps are used as heating elements. Because of its physical
characteristics, the cooktop heats more quickly, less afterheat remains, and only the plate heats
up while the adjacent surface remains cool. Also, these cooktops have a smooth surface and
are thus easier to clean, but they only work with flat-bottomed cookware and are markedly more
expensive. A third technology—developed first for professional kitchens, but today also entering
the domestic market—is induction stoves. These heat the cookware directly through
electromagnetic induction and thus require pots and pans with ferromagnetic bottoms. Induction
stoves also often have a glass-ceramic surface. Electric stoves are very popular today, especially
in urban and suburban areas.
8.2 TYPES
There are two types of electric stoves, namely Open type and Closed type. In open type,
the heating element is made of Nichrome wire. It possesses high resistivity, and withstands a
working temperature of about 900
0
C.
8.3 CONSTRUCTION
Heater Plate : A porcelain plate with a groove is made. It houses the Nichrome wire in a coil
form. The heater plate is made of porcelain. Porcelain withstands high temperature and remains
as a good insulator even at high temperatures. The coiled Nichrome heating element is housed
in the grooves. The grooves are designed with projections at various places, as shown in Fig.
8.1. The projections prevent the heating element from coming out of the grooves.
Body : A body is provided to house the heater plate in it. It is made of cast iron painted or
electroplated. The socket is fixed to the body, as shown in Fig. 8.2. An insulated handle is fixed
on the body for safe handling.
Fig. 8.1 - Heater Plate
Connecting leads: The lead wires should have a larger cross-section made of bare copper,
insulated with porcelain beads or glass beads. The beads are connected to the socket terminals
and heater plate terminals, as shown in Fig. 8.3.
Fig. 8.2 - Body