Refrigerant Circuit - Carrier SUPRA 850Mt Operation And Service Manual

- Cut out one side of the diodes.
- Check those diodes with an ohmeter.
- The diode is conforme if it has an infinite
resistance in one direction and a resistance of
0 in the other. If the resistance is infinite in
both directions or if it is at 0 in both directions,
the diode is broken.
e. Check of the winding resistor (see generator
resistance values section 2.5)
OHMETER
With an ohmeter:
- Stator: by the output wires (Check the
connection).
- Rotor: requires to remove the rotor and to cut
out the diodes.
f. Checking of the connectors
If the generator would not provide electricity, check
that the connectors are well crimped
g. Assembly phase
- Mount the stator/rotor to the flange fasten the
4 bolts.
- For the reassembly of the tested generator,
the tightening torques (N.m) for the fixation of
the front cover, stator and rear cover onto the
casing are:
Versions
54--60029--00
54--60029--01
54--60032--00
54--00603--00
54--00603--01
ROTOR
Torque values
4N.m ¦ 1N.m
5N.m ¦ 1N.m
(screw M6)
2-32

2.11 REFRIGERANT CIRCUIT

2.11.1 Cooling mode
when cooling, the unit operates as a vapor compres-
sion refrigeration system. The main components of the
system are the reciprocating compressor, air-cooled
condenser, thermostatic expansion valve, direct expan-
sion evaporator, and liquid line solenoid valve.
The compressor raises the temperature and
pressure of the refrigerant and it passes through a
normally open Main Heat Valve (MHV), through a check
valve into the condenser. The condenser fan circulates
surrounding air over the outside of the condenser tubes.
Heat transfer is then established from the refrigerant
gas (inside the tubes) to the condenser air (flowing over
the tubes). The condenser tubes have fins designed to
improve the transfer of heat. This removal of heat
causes the refrigerant to liquefy. Liquid refrigerant flows
from the condenser and through a check valve to the
receiver.
The receiver stores the additional charge necessary
for low ambient operation and for heating and defrost
modes. The refrigerant leaves the receiver and flows
through a manual receiver shutoff valve (king valve).
The refrigerant then flows through the subcooler.
The subcooler occupies a portion of the main
condensing coil surface and gives off further heat to the
passing air.
The refrigerant then flows through a filter-drier
where an absorbent keeps the refrigerant clean anddry.
The refrigerant thenflows throughthe accumulator /
heat exchanger and then to the liquid solenoid valves
(LSV). These solenoids are electrically energized when
in cooling mode and allow the liquid refrigerant to flow
through the externally
expansion valve (TXV), which reduces the pressure of
the liquid and meters the flow of liquid refrigerant to the
evaporator to obtain maximum use of the evaporator
heat transfer surface.
The evaporator tubes have aluminum fins to
increase heat transfer; heat is removed from the air
circulated through the evaporator. This cold air is
circulated throughout the box to maintain the cargo at
the desired temperature.
The transfer of heat from the air to the low
temperature liquid refrigerant causes the liquid to
vaporize. This low temperature, low pressure vapor
passes into the accumulator tank. The compressor
draws the vapor out of the accumulator through a
pick-up tube which is equipped with a metering orifice.
This orifice prevents the accumulation of oil in the
accumulator tank. The metering orifice is calibrated to
control the rate of oil flowing back to the compressor.
The vapor refrigerant then enters the compressor
pressure regulating valve (CPR), which regulates
refrigerant pressure enteringthe compressor, where the
cycle starts over.
equalized thermostatic
62--611XX- -20 (03/04)