Fronius Agilo 75.0 - Manual (Page 19)

17
EN
Functional principle
Functional princi-
ple The inverter operates fully automatically. The control module starts monitoring the grid volt-
age and frequency as soon as the solar modules produce enough energy after sunrise.
When insolation has reached a sufficient level, the solar inverter will start to feed energy
into the grid.
The inverter works in a way that ensures the maximum power possible is obtained from the
solar modules.
This is known as "Maximum Power Point Tracking" (MPPT).
As soon after dusk as the power available to feed into the mains falls below a sufficient
level, the inverter disconnects from the mains supply. It retains all its settings and stored
data.
Cooling of the in-
verter through
forced-air ventila-
tion Cooling of the inverter is performed by a forced-air ventilation system via a temperature-
controlled radial fan. Air is sucked in from the front and fed, via a sealed duct, through the
electronics compartment, before passing directly over the inductors and dissipating up-
wards.
The sealed air duct prevents the electronics compartment from coming into contact with
the ambient air. This approach largely prevents any contamination of the electronics com-
partment.
The speed of the fan and temperature of the intake air are monitored.
The variable-speed, ball-bearing mounted fans in the inverter permit the following:
-
optimum cooling of the inverter
- a higher level of efficiency
- cooler parts, therefore a longer service life
- lowest-possible energy consumption and noise levels
Power derating To protect the inverter if adequate heat dissipation is not possible, even with the fans run-
ning at full speed (e.g. when installed in containers without proper heat dissipation meas-
ures), the operation known as power derating takes place above an ambient temperature
of approximately 40 °C.
Power derating briefly reduces the power of the inverter to prevent the temperature ex-
ceeding its permitted limit.
The inverter remains operational for as long as possible without stopping.
Solar module
grounding The inverter is designed for use with non-grounded solar modules and those grounded on
the negative pole.
Grounding of the solar module on the negative pole is carried out inside the inverter via a
fuse holder equipped with a corresponding fuse as required.