LG GR-349SQF.CEWQEHU, Service Manual

Page: 9 / 36

1 COMPRESSOR
1) Role
The compressor intakes low temperature and low pressure
gas evaporated from Evaporator of the Refrigerator, and
condenses this gas to high temperature and high pressure
gas, and then plays delivering role to Condenser.
2) Composition
The Compressor is Composed of Compressor Apparatus
compressing gas, Compressor Motor moving Compressor
Apparatus and Case protecting Compressor Apparatus
and Motor. There are PTC-Starter, and Over Load
Protector (OLP) in the Compressor outside. On the other
hand, because the Compressor consists of 1/1000mm processing
precision components and is sealed after production in absence
of dust or humidity, deal and repair with care.
3) Note for Usage
(1) Be careful not to allow over-voltage and over-current.
(2) No Strike
If applying forcible power or strike (dropping or careless
dealing), poor operation and noise may occur.
(3) Use proper electric components appropriate to the
Compressor.
(4) Note to Keep Compressor.
If Compressor gets wet in the rain and rust in the pin of
Hermetic Terminal, the result may be poor operation
and poor contact may cause.
(5) Be careful that dust, humidity, and flux welding don't
inflow in the Compressor inside in replacing the
Compressor. Dust, humidity, and flux due to welding
which inflows to Cylinder may cause lockage and noise.
2 PTC-STARTER
1) Composition of PTC-Starter
(1) PTC (Positive Temperature Coefficient) is a no-contact
semiconductor starting device which uses ceramic
material and this material consists of BaTiO
3
.
(2) The higher the temperature is, the higher becomes the
resistance value. These features are used as starting
device for the Motor.
2) Role of PTC-Starter
(1) PTC is attached to Hermetic Compressor used for
Refrigerator, Show Case and starts Motor.
(2) Compressor for household refrigerator applies to
single-phase induction Motor.
For normal operation of the single-phase induction
motor, in the starting operation flows in both main coil
and sub-coil. After the starting is over, the current in
subcoil is cut off. The proper features of PTC play all
the above roles. So, PTC is used as a motor starting
device.
3) PTC-Applied Circuit Diagram
●
According to Starting Method for the Motor
4) Motor Restarting and PTC Cooling
(1) For restarting after power off during normal
Compressor Motor operation, plug the power cord after
5 min. for pressure balance of Refrigerating Cycle and
PTC cooling.
(2) During normal operation of the Compressor Motor, PTC
elements generate heat continuously. Therefore,
if PTC isn't cooled for a while after the power has been
shut off, Motor can't operate again.
5) Relation of PTC-Starter and OLP
(1) If the power is off during operation of Compressor and
the power is on before the PTC is cooled, (instant shut-
off within 2 min. or reconnect a power plug due to
misconnecting), the PTC isn't cooled and a resistance
value grows. As a result, current can't flow to the sub-
coil and the Motor can't operate and the OLP operates
by flowing over current in only in the main-coil.
(2) While the OLP repeats on and off operation about 3-5
times, PTC is cooled and Compressor Motor performs
normal operation.
If OLP doesn't operate when PTC is not cooled,
Compressor Motor is worn away and causes circuit-
short and fire. Therefore, use a properly fixed OLP
without fail.
6) Note to Use PTC-Starter
(1) Be careful not to allow over-voltage and over-current.
(2) No Strike
Don't apply a forcible power or strike.
(3) Keep apart from any liquid.
If liquid such as oil or water away enter the PTC,
PTC materials it may break due to insulation
breakdown of the material itself.
(4) Don't change PTC at your convenience.
Don't disassemble PTC and mold. If the exterior to the
PTC-starter is damaged, resistance value is altered and
it may cause poor starting of the compressor motor
may cause.
(5) Use a properly fixed PTC.
PTC STARTER
HERMETIC
TERMINAL
COMPRESSOR
MOTOR
C
M
S
M
3
6
5
S
PTC
OVERLOAD PROTECTOR(O.L.P)
RSIR
Figure 19
ADJUSTMENT
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