by Warpspeed » Sat Jan 04, 2014 8:21 am
Some of the newer small standby power generators are now what they call "inverter generators".
These use a standard ac alternator, the output of which is rectified to produce a high dc voltage, which in turn drives an inverter stage that produces the outgiong 240v 50Hz ac power.
The advantages of doing this are many.
A "normal" 240 volt ac machine needs to be run up to exact speed and very carefully phase synchronised to the mains before you can close the electrical connection. It then needs to run at constant fixed speed, regardless of load.
With an indpendant isolated power generator, it can just be started up and run, but if you expect 50 Hz from it, it still needs to run at a fixed RPM regardless of load. This can be noisy and inefficient at very low load.
What the inverter generator does, it allows the engine to run at whatever speed it needs to run to generate enough dc power. The inverter can then ELECTRONICALLY output 240 volts and 50Hz quite independantly of engine speed. At very low loads the engine can perhaps tick over at just above fast idle speed, saving fuel, noise, and engine wear. Switch in the big electrical load, and the engine quickly throttles up to max power at full RPM. And your 240v and 50Hz stays constant.
With a microprocessor and a few "smarts" you could just connect it up, push the start button, and away it goes all by itself without any need to do anything else.
Just like a grid tie inverter, the electronics keeps the inverter mains synchronised.