Product Manual

Protective and warning devices
44 firstAir screw compressor FAS03 – 37
8 Protective and warning devices
8.1 Motor overload protection
There are two electric motors in the screw compressor – a main drive motor and a motor for the cooling
air fan. When the operating current exceeds the set upper limit for the protective device under normal
operating conditions, the overload protection device automatically shuts down the power supply. After
shutdown, the screw compressor starts up again automatically if it has not otherwise been reset by press-
ing the reset switch manually. The current protection device is set at the factory, and this is very important
for protection when the compressor is operating normally. These settings must not be changed without
authorisation.
If a motor overload occurs during operation, please contact your service partner immediately. Otherwise
there is a danger of further damage.
8.2 Compressed air final temperature – excess temperature protection
The maximum compressed air final temperature of the system totals 95 °C. At temperatures above this
value, the display will flash and an alarm is triggered. If the temperature exceeds 100 °C, the system
automatically shuts down the power supply. There are many possible reasons for an excessively high
temperature at the compressed air outlet, with the most frequent being a high level of contaminants in the
Oil cooler. When the fins of the Oil cooler are dusty, the cold air can no longer pass the cooler freely, and
the temperature gradually increases and causes the system to shut down after reaching the correspond-
ing value. This is why the fins need to be cleaned in short intervals.
The maximum ambient temperature of the screw compressor totals 45 °C. Consequently, an installation
location with a low ambient temperature and good ventilation must be chosen whenever possible. If the
excess temperature protection is tripped, the start circuit of the system is stopped; pressing the reset
button allows the system to be restarted.