6-16T -296
a. Assemble the motor and plastic spacer onto the sta-
tor.
b. Apply loctite to the 1/4-20 x 3/4 long bolts and torque
to 0.81 mkg (70 inch-pounds).
c. Place one 5/8 flat washer on the shoulder of the fan
motorshaft.Insertthekeyinthekeywayandlubricate
the fan motor shaft and threads with a graphite-oil
solution (such as Never-seez).
d. Install the fan onto the motor shaft. Place one 5/8 flat
washerwitha5/8-18locknutontothemotorshaftand
torque to 40 foot-pounds.
e. Install the evaporator fan assembly in reverse order
ofremoval. Torquethefour1/4-20clampbolts to0.81
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 F AN MOTOR CAPACITORS
Units areequippedwithoneof2 types of evaporator fan
motors, single, and dual capacitor . The evaporator fan
motors are of the permanent-split capacitor type.
6.17.1 When To Check For A Defective Capacitor
a. Fan motor will not changespeed. Forexample: inthe
conventionalperishable mode, themotors shouldrun
in high speed. In the economy perishable mode they
shouldswitchspeedsandinthefrozenmode,themo-
tors should run in low speed.
NOTE
The evaporator fan motors will always start in
high speed.
b. Motor running inwrong direction (after checking for
correct wiring application).
c. Motor will not start, and IP-EM’s are not open.
6.17.2 Removing The Capacitor
W ARNING
Make sure power to the unit is OFF and
power plug disconnected before removing
capacitor(s).
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. The capacitor may be serviced after discon-
necting power plug.
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
oftheevaporator fanassembly,refertosection6.16.
W ARNING
With power OFF discharge the capacitor
before disconnecting the circuit wiring.
6.17.3 Checking The Capacitor
If the capacitor is suspected of malfunction, you may
choosetosimply replaceit. 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
terminalsandobservethemeterneedle.If thecapacitor
is good, the needle will make a rapid swing toward zero
resistance and then gradually swing back toward avery
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 a
analyzer are its ability to locate capacitors that have
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 SUCTION MODULATION VALVE
On start up of the unit, the valve will reset to a known
open position. This is accomplished by assuming the
valve was fully open, driving it fully closed, resetting the
percentage open to zero, then opening toa known21%
staging position.
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