Mitsubishi Electric City Multi R2 Series, Manual

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Conventional model (YLM)
Latest model (YNW)
Crank angle (deg)
Discharge
pressure
Intake
pressure
Compression chamber (MPaG)
Multi-port
Conventional
Over-compression area can be
eliminated in this structure
The compressor, known as the heart of the air conditioner, has been improved. A centrifugal force canceling mechanism and
a multi-port mechanism have been developed. In addition, we have mounted a high-efficiency motor. The synergetic effect of
these latest technologies increases the compressor performance and efficiency, and also helps to improve the performance
of the outdoor unit.
The structure of the scroll compressor causes a centrifugal force during operation. Conventionally, that centrifugal force is applied onto the scroll section.
This causes refrigerant to leak, and restricts the increase in rotational speed to a maximum of 120rps.
With the latest compressor, the latest structure (centrifugal force canceling mechanism) has been mounted to suppress the centrifugal force. This mecha-
nism successfully suppresses the centrifugal force generated at the scroll section, reduces refrigerant leakage losses, and increases the compressor
efficiency. The maximum rotational speed has been increased from the conventional 120rps to 140rps.
This mechanism also speeds up the start of operation, and enables operations such as preheat defrost operation and the smooth auto-shift startup mode.
Compressor with centrifugal force canceling mechanism
Partial
load
Operation pattern
Rating, high
pressure
difference
Open
Open
Open
Sub-port
Main port Valve
Valve
Valve
Open
Closed
Closed
Partial
load
Operation pattern
Rating, high
pressure
difference
Open Main port Valve Open
Conventional structure
Reduced over-compression loss (multi-port)
Multi-port structure
Fixed
scroll
Orbiting
scroll
Discharge port
Valve
Fixed
scroll
Orbiting
scroll
Valve Valve Valve
Discharge port Multi-port
Latest structure
Centrifugal force canceling mechanism (8 to 14HP)
The insulator section that traditionally created a
dead space is eliminated by insulating the motor’s
stator film. Since winding can be set in that
section, the winding area can be increased by
approx. 9%. The wire diameter has also been
increased by two ranks, so the resistance between
terminals is reduced, and the insulation distance
is shorter. This improves the motor’s operation
performance and contributes to high-efficiency
operation of the compressor.
Improved high-efficiency motor
Fixed scroll
Conventional mechanism
Orbiting scroll F
Slider
Vortex pressing load (F) is high.
Centrifugal force canceling mechanism
F
F’
Vortex pressing load (F-F’) is low.
Centrifugal force
cancelling slider
Spindle
Large loss Small loss
Latest structure
Centrifugal force
applied on scroll
section: Large
Refrigerants leakage
loss: Large
Max. speed 120rps
Centrifugal force
applied on scroll
section: Small
Refrigerant leakage
loss: Small
Max. speed 140rps
The sub-port is opened during partial load
operation to discharge the over-compressed gas.
Multi-port
When the target discharge pressure is
reached, the multiport opens, and the gas
refrigerant is discharged. This reduces drive
losses caused by over-compression.
Conventional model
Conventionally, gas refrigerant is compressed
to a set pressure, and then lowered to the
target discharge pressure at which it is
discharged. This causes drive losses from
over-compression.
The motor can be wound in the section where the
insulator was, and a larger wire diameter can be used.
The insulator section is large, and the
area where the copper wire can be wound
is small.
15
15
120
140
Rotational speed (rps)
Compressor ef
ficiency
With canceling mechanism
Improved
compressor
efficiency
Max. speed 120rps 140rps contribute
to speedy compressor start up
Insulator
Stator core
Insulation film
Insulator
Stator core
Insulation film
Magnet Wire
Magnet Wire
Increase in area
available for
winding
Efficient partial load operation is realised by avoiding over-
compression. With the scroll compressor, the distance of
the compression process in the scroll is usually fixed, so
over-compression occurs during low loads and low rotation.
The latest compressor is equipped with two sub-ports in
addition to the conventional discharge port to reduce this
over-compression loss during low loads. In operating
conditions with a low compression rate, the distance in the
compression process is kept short by successfully avoiding
unnecessary compression, and contributing to efficient
partial load operation.
Multi-port mechanism
F: Centrifugal force applied on scroll section F’: Centrifugal force applied on cancelling slider
R2-Series EP R2-Series P Y-Series EP Y-Series P
16
YNW-Series (Y/R2)