GE PTV15SAMR, Техническое руководство по обслуживанию

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Page 26
VII. ADJUSTMENT
7.2 PTC-STARTER
7.2.1 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.
7.2.2 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 singlephase induction motor.
For normal operation of singlephase
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.
7.2.3 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.
7.2.4 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.
iii. If OLP doesn’t operate when PTC is
not cooled, compressor motor is worn
away and causes circuit-short and fire.
Therefore, use a proper fixed OLP
without fail.
7.2.5 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
PTGStarter, resistance value alters
and poor starting of Compressor
motor may cause.
v. Use a properly fixed PTG.