LG LRTBC1825T Service Servicing Precautions page 6

4. ADJUSTMENT
4-1COMPRESSOR
4-1-1 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.
4-1-2 Composition
The compressor includes overload protection. The PTC
starter and OLP (overload protector) are outside the
compressor. Since the compressor is manufactured to
tolerances of I micron, and is sealed in a dust - and
moisture - free environment, use extreme caution when
repairing it.
4-%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
handling}, poor operation and noise may occur.
(3) Use proper electtic 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 welding flux don't
contaminate the compressor inside when replacing the
Compressor. Dust, humidity, and flux due to welding
which contaminates the cylinder may cause leckage
and noise.
4-2 PTC-STARTER
4-2-1 Composition of PTC-Starter
(1) PTC (Positive Temperature Coefficient) is a no-contact
semiconductor starting device which uses ceramic
matedal consisting of BaTiO3.
(2) The higher the temperature is, the higher the resistance
value. These features are used as starting device for
the Motor.
4-2-2 Role of PTCoStarter
(1) PTC is attached to Hermetic Compressor used for
Refrigerator, Show Case, and starting 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 star0ng 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.
4-2-3 PTC-Apptied Circuit Diagram
• According to Starting Method for the Motor
OVERLOAD PROTECTOR(O.L.P)
F- -c-q COMPRESSOR
.......3_ iC)
PTC STARTER HERMETIC
TERMINAL
RSIR
Figure 19
4-2-4 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, the motor will not restart.
4-2-5 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 rain. or unplugging and reconnecting), the
PTC isn't cooled and a resistance value grows. As a
result, current can't flow to the sub-coil, 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, always use a properly
attached OLP.
4-2-6 Note to Use PTC-Starter
(1) Be careful not to allow over-voltage and over-current.
(2) Do not strike
Don't apply a forcible power or strike.
(3) Keep apart from any liquid.
tf liquid, such as oil or water away enters the PTC,
PTC materials may fail due to insulation breakdown of
the material itself.
(4) Don't change PTC at your convenience.
Don't disassemble PTC and case. ]f 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 attached PTC.
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