S-15B Capacitance Check; Checking Motors; S-16A Checking Fan & Blower Motor; Windings (Psc Motors) - Daikin DCG Series Service Instructions Manual

SERVICING

S-15B CAPACITANCE CHECK

Using a hookup as shown below, take the amperage and
voltage readings and use them in the formula:
VOLTMETER
AMMETER
TESTING CAPACITANCE
WARNING
Discharge capacitor through a 20 to 30 OHM
resistor before handling.
Capacitance (MFD) = 2650 X Amperage
S-16

CHECKING MOTORS

S-16A CHECKING FAN AND BLOWER MOTOR

WINDINGS (PSC MOTORS)

Applies only to units with PSC Motors
The auto reset fan motor overload is designed to protect the
motor against high temperature and high amperage condi-
tions by breaking the common circuit within the motor, similar
to the compressor internal overload. However, heat gener-
ated within the motor is faster to dissipate than the compres-
sor, allow at least 45 minutes for the overload to 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.
15 AMP
FUSE
CAPACITOR
Voltage
1. Remove the motor leads from its respective connection
points and capacitor (if applicable).
2. Check the continuity between each of the motor leads.
3. Touch one probe of the ohmmeter to the motor frame
(ground) and the other probe in turn to each lead.
If the windings do not test continuous or a reading is obtained
from lead to ground, replace the motor.
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 gas-
ket (if required) are not properly in place and secured, there
is a remote possibility if a terminal vents, that the vaporous
and liquid discharge can be ignited, spouting 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 essen-
tial 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 extin-
guished or turned off prior to servicing a system.

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.
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