OMD91046 rev D
12
1.2.1 Operation with non-linear load
A non-linear load is characterized by a high peak current versus its RMS value, that
in normal condition would introduce a distortion on the output voltage waveform. The
inverter is provided with an instantaneous voltage correction facility, completely
managed by the microprocessor, that provides to vary the PWM generation according to
the actual output waveform, in order to keep the THD within 5% even with loads having
crest factor equal to 3.
Picture 7 – Operation with non-linear load
1.2.2 Overload management
The inverter can provide continuously 100% of nominal load and can tolerate
overload conditions up to 125% for 10 minutes or 150% for 30 seconds.
Peak conditions such as take-off of engines or magnetic parts are managed limiting
the output current to 200% for 5 cycles, then reducing to 150%.
Any time output power grows above 100% the inverter keeps feeding the loads, while
the microprocessor activates the “thermal image” algorithm to calculate the power
overload based on the output current and duration of the overload.
User loads are powered by inverter output up to the end of maximum allowed time,
then the static switch transfers the load to the emergency line without interruption of
output power.
Picture 8 – Thermal image characteristic