SERVICING
43
1. Remove the leads from the compressor terminals.
See warnings S-17 before removing compressor
terminal cover.
2. Using an ohmmeter, test continuity between terminals S-
R, C-R, and C-S, on single phase units or terminals T2,
T2 and T3, on 3 phase units.
S
R
C
COMP
OHMMETER
TESTING COMPRESSOR WINDINGS
If either winding does not test continuous, replace the
compressor.
NOTE:
If an open compressor is indicated, allow ample time
for the internal overload to reset before replacing compressor.
S-17B GROUND TEST
If fuse, circuit breaker, ground fault protective device, etc.,
has tripped, this is a strong indication that an electrical
problem exists and must be found and corrected. The circuit
protective device rating must be checked, and its maximum
rating should coincide with that marked on the equipment
nameplate.
With the terminal protective cover in place, it is acceptable to
replace the fuse or reset the circuit breaker ONE TIME ONLY
to see if it was just a nuisance opening. If it opens again, DO
NOT continue to reset.
Disconnect all power to unit
, making sure that
all
power
legs are open.
1. DO NOT remove protective terminal cover. Disconnect
the three leads going to the compressor terminals at the
nearest point to the compressor.
2. Identify the leads and using a Megger, Hi-Potential
Ground Tester, or other suitable instrument which puts
out a voltage between 300 and 1500 volts, check for a
ground separately between each of the three leads and
ground (such as an unpainted tube on the compressor).
Do not use a low voltage output instrument such as a volt-
ohmmeter.
HI-POT
COMPRESSOR GROUND TEST
3. If a ground is indicated, then carefully remove the com-
pressor terminal protective cover and inspect for loose
leads or insulation breaks in the lead wires.
4. If no visual problems indicated, carefully remove the leads
at the compressor terminals.
WARNING
Damage can occur to the glass embedded terminals if
the leads are not properly removed. This can result in
terminal and hot oil discharging.
Carefully retest for ground, directly between compressor
terminals and ground.
5. If ground is indicated, replace the compressor.
S-17D OPERATION TEST
If the voltage, capacitor, overload and motor winding test fail
to show the cause for failure:
1. Remove unit wiring from disconnect switch and wire a test
cord to the disconnect switch.
NOTE:
The wire size of the test cord must equal the line wire
size and the fuse must be of the proper size and type.
2. With the protective terminal cover in place, use the three
leads to the compressor terminals that were discon-
nected at the nearest point to the compressor and
connect the common, start and run clips to the respective
leads.
3. Connect good capacitors of the right MFD and voltage
rating into the circuit as shown.
4. With power ON, close the switch.
WARNING
Line Voltage now present.
