heater, electric iron, room heater

1. 1.HEATER
2.ELECTRIC IRON
Electrical Aplience-1
Ahamed.H.A -JTO-En-SSITI-Hassan
Mod - 4
Unit - 1
Email: sciencemesenger@gmail.com mob: 98447 76095

2. Types of heater
 Exposed element type heater
 Enclosed element type heater
 In exposed type of heater the element is made of
Nichrome wire. It posses high resistivity &
withstand a working temperature of 9000C

3. PARTS OF EXPOSED TYPE HEATER
 Heater plate
 Porcelain plate with groove
is made
 The coiled element is
housed
 in the grove
 The plate thickness varies
from 10mm to 25mm
depending upon wattage
 The ends of the coiled
element are terminated
with bolt & nuts in the
plate itself

4. PARTS OF EXPOSED TYPE HEATER
 Body or Frame
 made of cast iron or
M.S.Sheet painted or
electroplated
 The socket is fixed to the
body

5. PARTS OF EXPOSED TYPE HEATER
Connecting leads
 Larger c/s made of
copper insulated
with procaine
beads
 The leads
connected to the
socket & heater
plate terminals

6. PARTS OF EXPOSED TYPE HEATER
 Grill stand
 Made of
chromium/Nickel plated
M.S.Rods & hinged to the
body
 It supports the vessels
kept on the heater & acts
as a barrier between
exposed element &
vessels

7. PARTS OF EXPOSED TYPE HEATER
 Heater socket
 Used for plugging the
power supply to
appliance

8. PARTS OF EXPOSED TYPE HEATER
 Coiled heating
element
 It is made of Nichrome
wire
 Selection of wire size &
length
 L= calculated resistance/
Resistance/m of selected
dia of wire

9. SAFETY PROCEDURE
 The insulation
resistance between
element & body is less
than 1MΏ
 User should avoid
spilling of food, array,
any particles on the
heater as it results in
blowing of the fuse or
breakage of element or
plate

10. Precautions while replacing the heater
 Check over
heated plug,
terminals, socket
etc
 Check cable
continuity &
insulation
 Check the body for
rust
 Check breakage of
body

11. DETERMINING THE LENGTH OF WIRE
Sl no Size of the wire Resistance in
Ohm/m at
5000c
Current in amps
to produce at
5000c
S.W.G Dia in mm
1 18 1.18 0.9744 12.6
2 20 0.90 1.7355 8.6
3 22 0.71 2.8707 6.3
4 24 0.56 4.6587 4.45
5 26 0.45 6.9595 3.5
6 28 0.375 10.269 2.8
7 30 0.315 14.665 2.3
8 32 0.28 19.291 1.99

12. Numerical problem
1. Calculate the length of heating element wire for a
heater 250V, 1000W working at 5000C
I = W/V = 1000/250 = 4A
R = V/I = 250/4 = 62.5 Ohms
L = R / R/m = 62.5/ 4.658 = 13.42m
So for 1KW/250V coil used 24 SWG of 13.5 m wire

14. Electric iron
 Non automatic iron
 Automatic iron
 Steam iron

17. Parts of Non-
Automatic iron

18. 1. power card
1.
2. sleeve
3. handle
4. top cover
5. pressure plate
6. asbestos sheet
7. heat element
8. mica insulation
9. sole plate
10. heat plate

20. STEPS TO EFFICIENT REPAIR
 Conduct visual test
 Listen to customer
complaint
 Conduct
preliminary test
 Repair & make final
test
 Prepare the iron for
delivery

21. Automatic Iron
 Handle : Bakelite,
thumb grip, pilot lamp
 Sole plate: chromium
plated C.I
 Thermostat: automatic
heat adjustment unit
 Heating element:
ribbon shaped nichrome
connecting lead to
thermostat & sole plate
 Flex(supply)card:
cotton braided 3core

23. Steam Iron
 No difference between stem
iron dry iron
 It has a small reservoir mounted
above the heating element
 A control valve on this allows
the water to drip in to the recess
in the sole plate
 When water drips on the hot
sole plate it is converted in to
steam & goes out through the
holes in the bottom of the sole
plate
 The amount of steam is
controlled by knob knob located
at the handle

24.  The invention relates to a method
of connecting a housing part (1) of
an iron to a water tank (2) of the
iron. The water tank (2)
comprises a top part (3) and a
bottom part (4). The method
includes a watertight connection
between these top and bottom
parts. To make a simple and
inexpensive connection between
the housing part (10) and the
water tank parts (3, 4) an edge
(15) of the housing part (1), an
edge (10) of the top part (3) of the
water tank (2) and an edge (8) of
the bottom part (4) of the water
tank (2) are connected to each
other in a single process step by
means of mirror welding.

25. Maintenance

26. Maintenance :
 When heating element found to be defective whole
sole plate is replaced
 Distilled water is recommended for filling. If
ordinary water used may results in depositing salt in
the tank & clog the entry & exit ports
 Salt deposit can be removed by filling the tank with
water diluted vinegar & plugging the iron to
supply & flush by steam control knob

27. Thermostat Switch
 It is a device for
keeping
temperature steady
 It has two types
1. Bi-metal type
2. Adjustable
type

28. Bi-Metal type Thermostat Switch

29.  Made of two strips of metal with different
expansion rates welded together
 Metal strips expands when heated & contract
when cooled
 One metal strips has high rate expansion & other
one is low rate
 When bi-metal strip heated both the metals in the
strip expand. But the one at the bottom expands
faster & forces the upper half to curl up or bend
away from contact point
 As the strip cools it straighten & restores

30. Adjustable type Thermostat switch

32.  By sliding or turning a control knob is used adjust
the heat of the appliance with in the specified limit
 The bi-metallic blade of thermostat seldom is the
source of problem most often trouble occurs because
of contact points getting pitted & oxidized through
repeated use
 Bi-metal thermostat open & close slowly & results
contacts are prone to arcing results in corrodes the
contacts
 A good thermostat shows zero ohm resistance

33. T H A N Q
The End