2 Features and benefits
TCGB0070 rev.3 - 04/2012
36
Lubrication
Bearing in mind that lubrication is one of the most important factors in the service life of a compressor, HITACHI has deve-
loped a system based on the pressure differences between the suction and discharge using a secondary pump at the base
of the compressor. As a result, all of the compressor’s moving parts are lubricated evenly, ensuring high reliability in terms
of its operating range, even at low frequencies.
Hitachi Air Conditioning Product SA 2008
.
1. Comercial information
MAIN FEATURES
Discharge
Roller Bearing
Synchronous
motor
Asymmetric Scroll
Oil Return Pipe
Sub-ball-bearing
structure
Trochoid oil pump
Suction
Protection against liquid return
When the compressor is at rest, the moving scroll rests on the casing. When the compressor starts to run, the pressure in
the chamber under the scroll builds up through two bleed holes in the medium pressure section of the compression stroke.
This pressure then forces the scroll up against the housing and seals the compression chamber. If liquid returns to the
compressor, the resulting increase in pressure forces the scroll downwards, breaking the seal and allowing the liquid to
pass back into the compressor body, where it will boil off due to the higher temperature.
Hitachi Air Conditioning Product SA 2008
.
1. Comercial information
MAIN FEATURES
Suction inlet
Gas outlet
Fixed scroll
Moving scroll
Housing
Medium pressure
chamber
“Oldham ring”
Shaft
Oilway
New design of stator coils (only for RAS-(4~6)H(V)RNME-AF)
The new design of the stator coils positioned to optimize the magnetic field significantly reduce heat losses, and increase
the motor’s efficiency at low speeds.
Compressor efficiency
New stator coil design
Current model
Ef
ficiency
rpm
