6
−
16
T
−
318
mkg (70 inch-pounds) Apply power momentarily to
check for proper fan rotation (refer to paragraph 2.3).
If fan spins backward, then motor wiring or motor is
defective.
f. Replace access panel making sure that panel does
not leak. Make sure that the T.I.R. locking device is
lockwired.
6.17 EVAPORATOR FAN MOTOR CAPACITOR
For units equipped with single permanent-split capacitor
fan motors.
6.17.1 When To Check For A Defective Capacitor
a. If the fan motor will not change speed. For example: in
perishable mode, the motors should run in high
speed, in economy perishable mode fans should
switch speeds and in frozen mode, the fans should
run in low speed.
NOTE
Evaporator fan motors always start in high speed.
b. Fan motor running in wrong direction (after checking
for correct wiring application).
c. Motor will not start and IP-EMs are not open.
6.17.2 Removing the Capacitor
WARNING
Make sure power to the unit is OFF and
power plug disconnected before servicing
capacitor(s).
WARNING
With power OFF discharge the capacitor
before disconnecting the circuit wiring.
Capacitors must be discharged properly before testing.
To discharge the capacitor, first turn the unit power OFF
and disconnect the unit power plug. Then place a
20,000 ohm, 2 watt resistor across the terminals of the
capacitor for approximately 30 seconds.
The capacitors are located on the motor and may be
removed by two methods:
1.
If container is empty
, open upper rear panel of the
unit.
2.
If container is full,
turn the unit power OFF and dis-
connect power plug. Remove the evaporator fan
motor access panel (see Figure 2-1). For removal of
the evaporator fan assembly, refer to section 6.16.
6.17.3 Checking the Capacitor
If the capacitor is suspected of malfunction, you may
choose to simply replace it. Direct replacement requires
a capacitor of the same value. Two methods for
checking capacitor function are:
1. Volt-ohmmeter set on RX 10,000 ohms.
Connect ohmmeter leads across the capacitor
terminals and observe the meter needle. If the capacitor
is good, the needle will make a rapid swing toward zero
resistance and then gradually swing back toward a very
high resistance reading.
If the capacitor has failed open, the ohmmeter needle
will not move when the meter probes touch the
terminals. If the capacitor is shorted, the needle will
swing to zero resistance position and stay there.
2. Capacitor analyzer:
The function of the analyzer is to read the microfarad
value of a capacitor and to detect insulation breakdown
under load conditions. The important advantages of an
analyzer are its ability to locate capacitors that have
either failed to hold their microfarad ratings or those that
are breaking down internally during operation. It is also
useful in identifying capacitors when their microfarad
rating marks have become unreadable.
6.18 EVAPORATOR SECTION CLEANING
Containers and Container units that are exposed to
certain fumigants may develop visible surface
corrosion. This corrosion will show up as a white powder
found on the inside of the container and on the reefer
unit evaporator stator and fan deck.
Analyses by Carrier Transicold environmental
specialists have identified the white powder as
consisting predominantly of aluminum oxide. Aluminum
oxide is a coarse crystalline deposit most likely the result
of surface corrosion on the aluminum parts within the
container. If left untreated over time, it may build up in
thickness and eventually flake as a light
−
weight white
powder.
The surface corrosion of aluminum is brought about by
exposure to chemicals such as sulfur dioxide and
possibly other fumigants that are commonly used for
fumigation and protection of some perishable cargo
such as grapes, for example. Fumigation is the process
by which a chemical is released into an enclosed area to
eliminate infestations of insects, termites, rodents,
weeds and soil
−
born disease.
Typically any aluminum oxide that becomes detached
from evaporator fan stators will be blown into the wet
evaporator coil where it will be caught and then flushed
out of the unit during routine defrost cycles.
However, it is still highly recommended that after
carrying cargo subject to fumigation procedures, that
the inside of the unit be thoroughly cleansed prior to
reuse.
Carrier Transicold has identified a fully biodegradable
and environmentally safe alkaline cleaning agent
(Tri
−
Pow’r
®
HD) for the unit. This will assist in helping to
remove the corrosive fumigation chemicals and
dislodging of the corrosive elements.
This cleaner is available from the Carrier Transicold
Performance Parts Group (PPG) and can be ordered
through any of the PPG locations; Part Number
NU4371
−
88.
As a general safety precaution, before using this
product, refer to and retain the Material Safety Data
(MSDS) sheet. This document can be found at:
www.nucalgon.com/products/coil_cleaners_tripower.htm
