Phase Reversal Module (Prm); Figure 8−32 Megohmmeter Connection To Ground Plate; Figure 8−33 High Voltage Contactors - Carrier VECTOR 6500 Operation & Service Manual

Figure 8−32 Megohmmeter Connection to Ground
c. Connect the remaining lead to the red wire at the T1
terminal of power supply contactor 1 (PSCON) See
Figure 8−33
d. Set the megohmmeter reading to 1000V.
e. Turn on the meter and record reading. It should be
greater than 200 MW.
f. If the reading is less than 200 MW, run the unit for 15
minutes to dry out the windings and test again. If the
reading does not improve to above 200 MW after run-
ning 15 minutes, check for a short to ground by:
S Visually inspecting the tested component for any poor
connections or chafed wires
S Isolating the component and wire harness.
S Retesting the harness and component (i.e. the motor
windings) with the megohmmeter to determine where
the short to ground is located
g. Continue testing each of the red wires on PSCON T2
and T3 terminals. Each should measure greater than
200 MW. If not, follow the procedure outlined in Step f.
above.
h. To complete the test, all high voltage contactor con-
nections must be tested on their T1, T2 and T3 ter-
minals. See Figure 8−33 The fuses and the Overload
Ground Fault Module (OGF) do not need to be tested.
i. Following the completion of all testing, reconnect the
generator ground wire at the unit ground plate.
Plate
8
7
6
1. Heater contactor 1 (1HTCON1)
2. Condenser motor contactor (CDCON)
3. Evaporator motor contactor (1EVCON)
4. Power supply contactor (PSCON)
5. Power supply contactor 2 (PSCON2)
6. Generator contactor (GENCON)
7. Heater contactor 2 (1HTCON2)
8. Compressor contactor (CCON)
Figure 8−33 High Voltage Contactors

8.9.2 Phase Reversal Module (PRM)

One principle of three phase motors is that the direction
of rotation will be reversed if any two wires going to the
motor are reversed. When operating on the generator,
the wiring is not changed and therefore the PRM is not
active. However, when operating on standby power, the
incoming power may be reversed. The function of the
phase reversal module is to monitor the incoming
standby power and reverse the power to the motors if
that incoming power will result in incorrect rotation.
When the unit is started in standby, power is supplied to
the PRM +12V terminal to activate the PRM. Refer to
wiring schematic, Section 10. Once the PRM is
activated, it will provide a 12VDC power signal to the
microprocessor at terminal 5MP04 to signal the
microprocessor that Standby Operation has been
selected and high voltage has been detected at the
power plug. The PRM has two output contacts PRM IN
S1 and PRM IN S2. If incoming power is correct, the
PRM IN S1 contact is closed, energizing PSCON to
supply power to the motors. If any two incoming power
wires are reversed, the PRM IN S2 contact are closed,
energizing PSCON2 to supply power to the motors.
Both PSCON and PSCON2 have a set of normally
closed auxiliary contacts wired in series with the "other"
contactor to prevent energizing of both contactors at the
same time.
To test the PRM:
a. Check for 460 VAC power from the power plug to the
PRM. If required, correct wiring or power source.
8−33
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2
3
4
5
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