Product manual

KPMWC00905-10EN - page 5/24
General characteristics
Cabinet and structure
The cabinet is made of galvanized steel sheet and painted to provide a high resistance to corrosion. Colour Ivory White
(Munsell code 5Y7.5/1) (±RAL7044).
Frictionless Centrifugal compressor with magnetic bearings
The frictionless Centrifugal compressor with magnetic bearings and integrated VFD is an innovative compressor that
allows great unit efficiency and reliability.
The compressor’s one moving part (rotor shaft and impellers) is directly put in rotation by the permanent magnet direct
drive motor and kept levitated by a digitally controlled magnetic bearing system; the speed of rotation reduces as the
condensing temperature and/or cooling load reduces. Movable inlet guide vanes, activated by step motor, redirect gas
flow into the first stage impeller during low loads, after the compressor has reached minimum speed.
Fig.1
Motor
Variable Speed Permanent Magnet Direct Drive Motor (Fig.2), also known as ‘brushless’, is a synchronous motor,
refrigerant cooled and fully protected with thermistors.
Permanent magnets (Fig.3), placed onto the rotor, generate the magnetic flux that is necessary to provide torque.
VFD (Variable Frequency Drive) is required to adjust, depending on the load, the speed of rotation that normally is
between 18,000 and 48,000rpm.
Fig.2 Fig.3
Pressure and
temperature sensors
Inverter speed
control
Permanent Magnet
Direct Drive Motor
Motor and
bearing control
(the electronics)
Inlet Guide
Vanes
2 stage centrifugal
compressor