MovinCool CM25 Service Manual - Manual (Page 20)

Operation Section
20
4.2 Compressor
• The CM 25 is equipped with a variable speed compressor, which is driven by state of the art
inverter technology.
• A variable speed compressor automatically adjusts its speed as the heat load in the room
changes. With its soft start up, a variable speed compressor reduces start up wear on the
compressor and eliminates in-rush current resulting in no dip in the power supply.
• As an AC power signal is supplied to the inverter circuit, it is then rectified and converted into a
DC power signal with modulated frequency. This modulated frequency controls the speed of the
compressor.
• As the compressor speed decreases, the amount of refrigerant entering the evaporator also
decreases. This results in a more comfortable environment as the unit provides the appropriate
amount of desired cooling. As a result, the room is controlled with a much smaller temperature
swing than traditional control methods.
(1) Compressor construction
• The construction of a swing type compressor is
divided into two mechanisms; the drive
mechanism (compressor motor), and the
compression mechanism (compressor). When
the rotor shaft of the motor (drive mechanism)
turns, the piston (compression mechanism)
rotates to compress the refrigerant.
(2) Basic compressor operation
• The piston (compression mechanism) is set
eccentrically with a certain distance given from
the axis of the center of the cylinder. The
piston turns to compress the refrigerant in the
space between the cylinder and eccentrically
mounted piston. A swing bush absorbs the
lateral blade movement under piston action.
The blade partitions the space between the
suction side and the discharge side to keep
compressed refrigerant from returning to the suction side. There is no suction valve. The
discharge valve is designed not to open until the pressure of the refrigerant within the cylinder
reaches or exceeds discharge side pressure. As a result, the discharge valve prevents the
backward flow of refrigerant gas.
I003143
I003184
Discharge
Orifice
Cylinder
Swing Bush
Suction Orifice
Discharge Valve
Shaft
Piston