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Equipment and Test Procedures for Electrical Circuit Components | Up
Utilitiesman (Advanced) - Manual for electric, plumbing, water and other utilities | Next
Figure 14-43.—Typical hermetic system schematic wiring diagram. |
motor then operates properly, the old Klixon
(protector) should be destroyed. Klixons can
also be checked with an ohmmeter. Since the
contacts are closed at ambient temperature,
the meter should show continuity. When the
meter shows an open, the Klixon should be
replaced and destroyed.
Internal current temperature overloads
can be tested by making continuity checks.
Continuity checks must be made across
terminals C and S, C and R, and S and R.
When both C and S and C and R are open
and continuity is indicated across S and R,
the protector is open. When the temperature
is normal and the continuity test indicates the
overload contacts are open, the motor com-
pressor assembly must be replaced. When the
operating temperature is normal, the internal
current temperature overload contacts should
be closed.
turned OFF and the capacitor disconnected
and discharged with a 2 watt 20,000 ohm
resister. Set the meter on the 0 to 10,000
ohm scale and touch the meter probes to the
capacitor terminals. If the digital display
indicates 0 or low resistance and then climbs
towards high resistance, the capacitor is good.
If the display indicates 0 or low resistance and
stays there, the capacitor is shorted. If the
display stays blank, the capacitor is open.
Figure 14-42 shows these procedures.
HERMETIC ELECTRICAL
SCHEMATIC WIRING DIAGRAMS
All wiring circuits are built around four
requirements: a source of electrons, a place
for them to flow, a path for them to follow,
and a load to make use of and control the
flow. The schematic wiring diagram puts the
symbol and line representation on paper in a
manner that allows instant identification of all
f o u r r e q u i r e m e n t s . I t t e l l s t h e s e r v i c e
member how and why a unit works as it does.
CAPACITOR TEST
The best test for a questionable motor
capacitor is to try a new one of the correct
size. If the motor operates properly, the old
c a p a c i t o r i s d e f e c t i v e a n d s h o u l d b e
destroyed. Capacitors can also be tested with
o h m m e t e r . F i r s t , t h e p o w e r m u s t b e
In the schematic wiring diagram, the
source of electrons is a line drawn on one
s i d e o f t h e d i a g r a m a n d i t i s u s u a l l y
designated as L1. Any and all points on this
line have a surplus of electrons. On the
opposite side, a line is drawn representing a
s h o r t a g e o f e l e c t r o n s a n d i t i s u s u a l l y
designated as L2. There is a potential for
e l e c t r o n f l o w b e t w e e n t h e t w o w i r e s
represented by L1 and L2. When a load is
inserted between L1 and L2, current flows and
the load functions.
Figure 14-43 is a typical schematic
diagram for a hermetic electrical system.
Figure 14-44 is a wiring schematic and a
w i r i n g d e t a i l f o r a t y p i c a l r o o m a i r -
conditioner.
Figure 14-42.—Testing capacitors with
an ohmmeter.
14-25
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