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Verfügbare Sprachen
Verfügbare Sprachen
[%]
1 0
6
140
120
M
100
I
80
60
40
20
P
0
0
10
20
30
0
0
500
1100
1700
0
0
100
200
Fig. 4: Operating characteristics of an ORBIT compressor motor (E..7 series: max. 65 Hz) for operation with frequency inverter (400 V/3/50 Hz)
with reserve.
P: max. compressor power consumption
M: max. torque of the motor at compressor shaft
I: max. compressor current consumption
f: frequency (frequency inverter output)
U: voltage (frequency inverter output)
3.2
Application range
For a safe compressor operation with frequency inverter, the following limiting factors must be strictly observed:
• minimum and maximum frequency (see below)
• maximum motor temperature
• maximum discharge gas temperature and pressure difference (p
• maximum and minimum discharge pressure
• maximum operating current of the compressor
• maximum evaporating temperature
• minimum pressure difference (p
• minimum suction pressure
These limits define the application limits (see below) and can vary according to frequency ranges and operating
conditions.
Speed and frequency ranges
Minimum frequency is 35 resp. 44 Hz: This has been demonstrated as the minimum safe speed required to deliver
adequate lubrication to the compressor bearing system. Running at lower speeds risks loss of lubrication and bear-
ing failure.
The maximum frequency is due to the increasing centrifugal forces which affect the mechanial stability of the
scrolls.
EST-420-6 // PDF Download
40
50
60
70
2300
2900
3500
4100
400 .................... 400 U [V]
300
– p
)
C
O
P
I
M
80
f [Hz]
-1
4700
n [min
]
– p
C
)
O
45
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