Inverter systems can be in-corporated with generator systems to attain longer run-time when there is a cut in the mains power supply.The essential and critical loads require undisturbed power supply when the mains AC power supply falls for extended periods.The inverter can be used to power the critical and essential loads when the power supply fails.The generator can be started automatically or manually when the power cut extends for longer periods and the inverter battery becomes exhausted.In such a condition the inverter alone cannot provide necessary to the loads.
Instead of drawing power from the battery,the inverter draws power from the generator and continues to power the critical loads.In such a configuration the run time of the inverter will not be affected by the capacity of the battery.The extended run time can be also achieved by using extra batteries.But this method proves to be more costly and space consuming.Also unlimited run time cannot be attained by using extra batteries.
An inverter which is backed up by an AC generator is one of the most easy method to produce a power protection for prolonged time at minimum cost.Also the generator must be selected such that it can handle the effects of sudden changes in the load.The common habit is to use a generator with a rating of around 6 to 8 times that of the load.As an example a generator of 8KVA can be used for a house drawing 1KVA power.This could prevent a lot of problems associated with the generator as well as inverter.Also special care must bu taken to assure that the inverter will function properly with the AC generator.The common scheme for connecting an inverter with a generator is shown below.
