Mitsubishi Electric Y Series Manual page 16

YNW-Series (Y/R2)
16
Compressor with centrifugal force canceling mechanism
Y-Series EP Y-Series
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.
Centrifugal force canceling mechanism (8 to 14HP)
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.
Conventional mechanism
Large loss
Vortex pressing load (F) is high.
Fixed scroll
Orbiting scroll F
Slider
F: Centrifugal force applied on scroll section F': Centrifugal force applied on cancelling slider
Multi-port mechanism
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.
Conventional structure
Operation pattern
Partial
Main port Valve Open
Multi-port structure
Operation pattern
Partial
Main port Valve Open
Valve Open
Sub-port
Valve Open
The sub-port is opened during partial load
operation to discharge the over-compressed gas.
Reduced over-compression loss (multi-port)
Multi-port
Conventional
Intake
pressure
Crank angle (deg)
Over-compression area can be
eliminated in this structure
P R2-Series EP R2-Series P
Centrifugal force canceling mechanism
Small loss
Centrifugal force
applied on scroll
section: Large
Refrigerants leakage
Large
loss:
F'
Max. speed 120rps
Centrifugal force
cancelling slider
Spindle
Fixed
scroll
Rating, high
pressure
load
difference
Orbiting
scroll
Open
Discharge port
Latest structure
Rating, high
Valve
pressure
load
difference
Fixed
scroll
Open
Closed
Orbiting
scroll
Closed
Discharge port
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.
Discharge
pressure
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.
Vortex pressing load (F-F') is low.
Centrifugal force
applied on scroll
section: Small
F
Refrigerant leakage
Small
loss:
Max. speed 140rps
Latest structure
Improved high-efficiency motor
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.
Conventional model (YLM)
Valve
Valve Valve
The insulator section is large, and the
area where the copper wire can be wound
is small.
Multi-port
The motor can be wound in the section where the
insulator was, and a larger wire diameter can be used.
With canceling mechanism
15 120
15
Rotational speed (rps)
Max. speed 120rps 140rps contribute
to speedy compressor start up
Insulator
Magnet Wire
Stator core
Insulation film
Latest model (YNW)
Insulator
Magnet Wire
Stator core
Insulation film
Improved
compressor
efficiency
140
Increase in area
available for
winding