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5. Remove the PTC device from the
co mp re s so r.
6 . Us in g a n
o h m me te r, che ck th e
resistance between the PTC device
t e r m i n a l s . T h e o h m m e t e r s h o u l d
r e gi s t e r b e tw e e n 3 a n d 20 o hms.
An extreme variance from between 3 and
20 ohms indicates a defective PTC d'evice
w hich m u s t b e re p l a ce d .
NO TE : W E D IS C OU RA GE USIN G A
VOLTMETER
TO
CHECK
THE
PE RFO R MA N C E OF TH E PT C D EVICE
BECAUSE THE TEST RESULTS ARE
INFLUENCED BY SEVERAL FACTORS,
SUCH AS I TS D E P E N D EN CE
O N T H E L INE
VO L T A GE T O TH E C OMPR ESSO R , T HE
RESPONSE CHARACTERISTIC OF THE
VOLTMETER AND THE PTC DEVICE
TE M P E R A TU RE A T T HE T IME T HE
C OM PR E S S OR
I S E N ER G IZ E D.
REPLACING PTC DEVICE
1 . U n p l u g t h e l i n e c o r d .
2. Di s co n n e ct t h e P T C d evi ce fro m the
co m pr e sso r t e rm i n a ls.
3. Re m o ve th e l e a d w i re s fro m th e P T C
d e v i ce t e rm i n a l s.
4. Re pl a ce th e d e v i ce a n d reco n n e ct th e
w i re s t o th e p ro p e r te rmi n a ls.
RUN CAPACITOR
T h e ru n c ap a c it o r i s m ou n te d a dj a ce nt to
th e
c o mp re s so r. l t
i s
e le ctri cally
c on ne c t e d b e tw e e n t he ru n an d sta rt
w i n d i n g s a n d i n p a r a l l e l w i t h t h e P T C
d ev i c e . Th e c a p a c i t o r is co n n e cte d to th e
co m pr essor cir cuit to provide t he r equired
phase difference between the start and
r u n w i n d i n g s f o r r u n n i n g t h e c o m p r e s s o r .
CAPACITOR FAILURES
Fa ilure of the capacit or may be caused by
( 1 ) a short cir cuit , ( 2) open cir cuit, ( 3) a
ca p acitor t hat is low in capacit ance.
A sh or t cir cuit will cause t he star t
win dings to be energized in t he start mode
a ll the tim e. The compressor could s tart
but
the
overload protector would
e ve nt ually tr ip, and sooner or later, tr ip
c o n t i n u o u s l y .
An open circuit should, under norm al
co n ditions, allow t he compr essor to star t.
Un d er a heavy r unning load, how ever , the
c o m p r e s s o r w i l l u s u a l l y t r i p o n t h e
o ve r load.
A capacit or m ay lose capacitance by a
lo ss of its elect rolyt ic proper ties. The
c o m p r e s s o r w o u l d r u n u n d e r a l i g h t l o a d ,
b u t w o u l d t r i p , o n t h e o v e r l o a d i n h i g h
a m b i e n t c o n d i t i o n s .
TESTING CAPACITOR
CAUTION: DISCHARGE A CAPACITOR
BEFORE HANDLING. SHORT ACROSS /TS
TERMINALS, US/NG A RES/STOR WITH A
MINIMUM RES/STANCE OF lOOO OHMS,
W e
recommend using a
caPac itor
analyzer when testing. Preferably a solid
sta te unit t hat measures capacitance and
power factor of any capacitor, and has an
a u tom atic m eans of dischar ging the
ca p acitor thr ough r esistance.
4 - 1 8
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