2-4 
Specification  Range 
Storage temperature
 
–40°C to +70°C (–40°F to 
+158°F) 
Relative humidity 
(noncondensing)
 
10% to 95% 
 
Power Supply 
Check that the power supply of the installation site is stable. The 
centralized AC power system consisting of the AC mains, UPS, and 
user-supplied diesel generator should be:  
z  Easy to connect 
z  Safe to operate  
z  Flexible to dispatch  
z  Convenient to maintain 
The low-voltage power supply should adopt the single-phase 
three-wire system. 
Table 2-4 lists the nominal voltage and frequency 
of the low-voltage AC power supply.  
Table 2-4 Nominal voltage and frequency of the low-voltage AC 
power supply 
Power supply  Nominal voltage  Stable frequency 
Single-phase 
three-wire (V)
 
100 VAC to 240 
VAC 
50/60 Hz