Reference Conditions And Limitations - Atlas Copco SF 15+ Instruction Book

• For supply cables larger than AWG8: use maximum allowed ampacity of the selected
supply cables and compare with value in table below (see CEC Part 1 table 17)
< 100 A: use AWG8
< 200 A: use AWG6
< 300 A: use AWG4
Always check the voltage drop over the cable (less than 5 % of the nominal voltage is
recommended).
Example of supply cable calculation: I
recommended fuse = 40 A
• Single supply cables (3 phases + 1 PE - configuration (1)):
• I = 28 A + 25 % = 28 x 1.25 = 35 A
• For AWG8, the maximum current at 40 °C is 50 A x 0.88 = 44 A, which is sufficient =>
use AWG8.
• Install the prescribed maximum fuse (40 A) on each cable
• Parallel supply cable (2 x 3 phases + 2 PE - configuration (2)):
• I = (28 A + 25%)/2 = (28 x 1.25)/2 = 17.5 A
• For a AWG14, the maximum current at 40 °C is 20 A x 0.88 x 0.8 = 14.1 A, which is
insufficient. For an AWG14, the maximum current is 25 x 0.88 x 0.8 = 17.6 A. So 2
parallel cables of 3 x AWG12 + 2 x AWG12 are sufficient.
• Install 20 A fuses on each cable.
9.2

Reference conditions and limitations

Reference conditions
Air inlet pressure (absolute)
Air inlet pressure (absolute)
Air inlet temperature
Air inlet temperature
Relative humidity
Working pressure
Limits
Maximum working pressure
Maximum inlet temperature
Maximum inlet temperature
Minimum ambient temperature
Minimum ambient temperature
102
= 28 A, maximum ambient temperature is 40°C,
tot
bar
psi
ºC
ºF
%
ºC
ºF
ºC
ºF
Instruction book
1
14.5
20
68
0
See section Compressor data
See section Compressor data
40
104
0
32
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