The DC-DC converter is optimized to connect on the frequency converter's dc bus/stage. This voltage is usually not filtered, has high EMI interference and leaves high leakage currents. The converter has a very robust input stage and filter, which provides safe operation even at very disturbing power supply. Duplicate 600V dc fuses are built-in, which saves space and money. At power outages, the motors act as generators and reset voltage to the frequency converter capacitors which, in turn, output voltage to the dc-dc converter. This means that 24V dc is maintained and a controlled stop can be performed.
The bonus effect gives 25% extra reserve with retained 24V which is an advantage when connected loads have high starting current.
The converter has polarity protection and minimal input current. In addition, there is a relay output (dc OK) that falls when the output voltage deviates more than 10% from the set value.
