Checking Compressor Windings; S-17A Resistance Test; S-17B Ground Test - Daikin DCH048 Series Service Instructions Manual

SERVICING
High Voltage
Connections
C L G N
1 2 3 4 5
Low Voltage Connections
EEM MOTOR CONNECTIONS
S-17 CHECKING COMPRESSOR WINDINGS
WARNING
Hermetic compressor electrical terminal venting can
be dangerous. When insulating material which
supports a hermetic compressor or electrical terminal
suddenly disintegrates due to physical abuse or as a
result of an electrical short between the terminal and
the compressor housing, the terminal may be
expelled, venting the vapor and liquid contents of the
compressor housing and system.
If the compressor terminal PROTECTIVE COVER and
gasket (if required) are not properly in place and se-
cured, there is a remote possibility if a terminal vents, that
the vaporous and liquid discharge can be ignited, spout-
ing flames several feet, causing potentially severe or fatal
injury to anyone in its path.
This discharge can be ignited external to the compressor
if the terminal cover is not properly in place and if the
discharge impinges on a sufficient heat source.
Ignition of the discharge can also occur at the venting
terminal or inside the compressor, if there is sufficient
contaminant air present in the system and an electrical
arc occurs as the terminal vents.
Ignition cannot occur at the venting terminal without the
presence of contaminant air, and cannot occur externally
from the venting terminal without the presence of an
external ignition source.
Therefore, proper evacuation of a hermetic system is
essential at the time of manufacture and during servicing.
To reduce the possibility of external ignition, all open
flame, electrical power, and other heat sources should be
extinguished or turned off prior to servicing a system.
3/16"
1/4"

S-17A RESISTANCE TEST

Each compressor is equipped with an internal overload.
The line break internal overload senses both motor amperage
and winding temperature. High motor temperature or amper-
age heats the disc causing it to open, breaking the common
circuit within the compressor on single phase units.
Heat generated within the compressor shell, usually due to
recycling of the motor, high amperage or insufficient gas to
cool the motor, is slow to dissipate. Allow at least three to four
hours for it to cool and reset, then retest.
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing this unit. Multiple power
sources may be present. Failure to do so
may cause property damage, personal injury
or death.
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 T1,
T2 and T3, on 3 phase units.
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 compres-
sor.

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.
C
R
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COMP
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