Carrier 69NT40--541--200 TO 299 Operation And Service page 85

d. Using a voltmeter, and with the primary supply circuit
ON, check the primary (input) voltage (460 vac).
Next, check the secondary (output) voltage (230
vac). The transformer is defective if output voltage is
not available.
6.20 POWER FACTOR CORRECTOR
CAPACITORS (PFC)
The power factor corrector capacitors are of the
permanent-split capacitor type. There are a total of
three capacitors with discharge resistors enclosed in a
single case.
a. When to check for a defective capacitor
The capacitors assist in correcting current draw by the
compressor. If one or more of the capacitors is faulty,
there will be an imbalance in current. In addition, the
power consumption of the unit will increase.
b. Removing the capacitor
WARNING
Make sure power to the unit is OFF and
power plug disconnected before removing
capacitor(s).
WARNING
Before removing
terminals must be checked for voltage with
a multimeter. The discharge resistors
installed on the unit (capacitors) should
bring the voltage to a safe level in a minute.
However, there may be a broken resistor
that retains voltage for a longer period, it is
highly recommended to wait 15 minutes
and to check for voltage.
1. The capacitors are located on the unit sidewall
above the evaporator fan deck, and
removed by two methods:
(a.) If container is empty, open upper rear panel of
the unit. The capacitors will be on the right and
may be serviced after disconnecting power
plug.
(b.) If container is full, turn the unit power OFF and
disconnect power plug. Remove the upper
fresh air makeup vent.
the capacitors the
may be
With power OFF discharge the capacitor
and disconnect the circuit wiring.
c. 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. The reading should read about
330,000 ohms (for a good capacitor) due to the
discharge resistors.
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
6.21 CONTROLLER
6.21.1 Handling Controller
Do not remove wire harnesses from con-
troller unless you are grounded to the unit
frame with a static safe wrist strap.
Unplug all controller connectors before
performing arc welding on any part of the
container.
The guidelines and cautions provided herein should be
followed when handling the Controller/DataCORDER
module. These precautions and procedures should be
implemented when replacing the module, when doing
6-19
WARNING
.
CAUTION
CAUTION
T--317