GE TBG440ANDR, Technician Service Manual

Page: 16 / 141

Page 16
V. ADJUSTMENT
5.2 PTC-STARTER
5.2.1 Composition of PTC-Starter
i. PTC (Positive Temperature
Coefficient) is no-contact
semiconductor starting device which
uses ceramic material and the
material consists of BaTiO
3
.
ii. The higher the temperature is, the
higher resistance value becomes.
These features are used as starting
device of motor.
5.2.2 Role of PTC-Starter
i. PTC is attached to hermetic
Compressor used for refrigerator,
show case and starts motor.
ii. Compressor for household
refrigerator applies single-phase
induction motor. For normal
operation of single-phase induction
motor, in the starting operation flows
in both main coil and sub coil. After
the starting is over, the current is cut
off in sub coil. The proper features
of PTC play the above all roles. So,
PTC is used as a starting device of
motor.
5.2.3 Motor Restarting and PTC Cooling
i. 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.
ii. During normal operation of
Compressor Motor, PTC elements
generate heat continuously.
Therefore, if PTC isn’t cooled for a
while after power off, Motor can’t
operate again.
5.2.4 Relation of PTC Starter and OLP
i. If power off during operation of
Compressor and power on before
PTC is cooled, (instant shut-off within
2 min. or reconnect a power plug due
to misconnecting), PTC isn’t cooled
and a resistance value grows. As a
result, current can’t flow to the sub-
coil and motor can’t operate and OLP
operates by flowing over current in
only main-coil.
ii. 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 cuases circuit-short
and fire. Therefore, use a proper
fixed OLP without fail.
5.2.5 Note to Use PTC-Starter
i. Be careful to over voltage and over
current.
ii. No Strike.
Don’t apply a forcible power or strike.
iii. Keep apart from any liquid
If liquid such as oil or water inflows
into PTC, PTC materials may break
due to insulation breakdown of
material itself.
iv. Don’t change PTC at your
convenience.
Don’t disassemble PTC and mold.
If damaging to outside of PTC-
Starter, resistance value alters and
poor starting of Compressor motor
may cause.
v. Use a properly fixed PTC.