Fronius Symo GEN24 3.0, Operating Instructions Manual, Page: 9 / 144

Backup power This system has backup power functions. This enables a replacement power supply to
be established in the event of a failure in the public grid.
Where an automatic backup power supply is installed, a backup power warning notice
(https://www.fronius.com/en/search-page, item number: 42,0409,0275) must be fitted on
the electrical distributor.
Maintenance and installation work in the home network requires both disconnection on
the utility side and deactivation of the replacement power mode by opening the integ-
rated DC disconnector on the inverter.
Depending on the insolation conditions and the battery state of charge, the backup
power supply is automatically deactivated and activated. This can cause the backup
power supply to unexpectedly return from standby mode. Therefore, installation work can
only be performed on the home network when the backup power supply is deactivated.
Influencing factors on the total power in backup power mode:
Reactive power
Electrical loads with a power factor not equal to 1 also require reactive power in addition
to effective power. The reactive power also loads the inverter. Therefore, to correctly cal-
culate the actual total power, it is not the rated power of the load that is relevant, but the
current caused by effective and reactive power.
Devices with a high reactive power are mainly electric motors such as:
-
Water pumps
- Circular saws
- Blowers and fans
High starting current
Electrical loads that need to accelerate a large mass usually require a high starting cur-
rent. This can be up to 10 times higher than the nominal current. The maximum current
of the inverter is available for the starting current. Loads with too high starting currents
therefore cannot be started/operated, even though the nominal power of the inverter sug-
gests that they can. When dimensioning of the backup power circuit, the connected load
power and any starting current must also be taken into account.
Devices with high starting currents are, for example:
-
Devices with electric motors (e.g. lifting platform, circular saws, planing bench)
- Devices with large transmission ratio and flywheel mass
- Devices with compressors (e.g. compressed air compressors, air conditioning sys-
tems)
IMPORTANT!
Very high starting currents can cause short-term distortion or a drop in output voltage.
The simultaneous operation of electronic devices in the same backup power supply sys-
tem should be avoided.
Load unbalance
When dimensioning three-phase backup power networks, the total output power and the
power output per phase of the inverter must be taken into account.
IMPORTANT!
The inverter may only be operated within the limits of its technical capabilities. Operation
outside of its technical capabilities can cause the inverter to shut down.
Data protection The user is responsible for the safekeeping of any changes made to the factory settings.
The manufacturer accepts no liability for any deleted personal settings.
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EN