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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: UPS and generator interaction?
Speaking on Deep Background, the Press Secretary whispered: > Does anyone know of a way to get a UPS to trigger a generator to start, and > to switch over to the generator power automatically or does this type of > thing just not exist? The UPS will have nothing to do with this. The generator would be connected to an Automatic Transfer Switch (really an A.T.Relay..) that would: a) Wait from several seconds up to a minute, to avoid false starts. b) Start the generator c) Transfer the load after the generator is going. If the UPS is plugged into a generator-fed outlet, it then goes back to charge. I *have* seen the issue others mentioned - where the USP would not recognize generator power. It was SmartUPS's and I'm still puzzled. The AC output did have some ringing[1] on the scope but it was not clear that was the cause. Note a Variac [autotransformer] would be of no help. What might would be a ferro-resonant ["Sola"] transformer. FR transformers use a big hunk of transformer iron, in effect a magnetic flywheel, to smooth out all kinds of dips, spikes and surges. But there's a heavy price for such - an unloaded 1000 watt Sola draws ~340 watts. Their efficiency is better at rated load, but they still make nice heaters. They also HUMMMMMMMM. FR's have another issue. The output voltage is not a function of input voltage[2] but *IS* a function of frequency! And they are BIG starting loads. Thus you load the generator with the FR regulator, it gulps and slows down, lowering the frequency, dropping the regulated output, the generator recovers and raises its frequency, so the voltage..... If the FR load is a fraction of the total load; it's usually not an issue. [And remember, the generator must run the HVAC unless all you want is an orderly shutdown within a few minutes..] [1] Here 'ringing' means sharp spikes in the should-be-smooth sine-wave output. [2] Within a wide range, say 105-135v in for a 120v model. But get outside of THAT, and...] -- A host is a host from coast to [email protected] & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433
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