Is your event in a remote location? Do you need more power than the building can give you? So you decide to hire a generator! Good, but why is the hire company offering you a Twin zero-interruption generator set?
Let's start at the beginning
A generator is an engine running on fuel oil, diesel or GNR (French non-road diesel), which drives an alternator and so produces electricity.
No rocket science so far, except that, to keep the voltage and frequency stable, the whole thing is managed by an electronic board. Still with me?
Every hire company will sing the praises of its generators. It is still an engine, with all the vagaries of mechanics and electronics. The whole thing is very reliable and servicing is done before every hire (at least at our suppliers), but a breakdown can always happen: there is no such thing as zero risk, just like with your car.
Enter the Twin zero-interruption generator set
Two generators connected together run at the same time: they synchronise and each supplies 50% of the load, each one sized to carry the whole load on its own.
If one of the two generators fails, the other takes over the missing 50% and, as it is already running, there is no interruption at all: electronic equipment stays powered and does not shut down.
Indeed, a computer that suffers even a micro-interruption may well end up with a dead hard drive as a result. Some lighting or sound consoles run on an operating system that needs several seconds, or even several minutes, to restart after a power cut. Needless to say, some productions do not take that risk and therefore use this system.
Bonus: in certain more specific cases, you can even go up to 3 or 4 synchronised generators (tri-pack, quadri-pack).