UPS and generator interaction?

Tue Mar 30 03:17:13 UTC 2004

On Mon, 29 Mar 2004, Laurence F. Sheldon, Jr. wrote:
> 
> > On Monday 29 March 2004 01:26 pm, Brian (nanog-list) wrote:
> > 
> >>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?
> > 
> > I think you are looking at it wrong,  you need an Automatic Transfer Switch.  
> > It connects to both commercial power and your generator, and provides a feed 
> > into your panels.    Your UPS's sit in front of the ATS, and provide clean 
> > power.  If/When you loose commercial power, the ATS will detect this and 
> > power on the generator, after a configurable amount of time it will switch to 
> > generator power, until commercial power comes back and is stable for X amount 
> > of time. 
> 
> We are talking about some significant energy levels here, and this
> is NOT a DIY project.  If the switch is hooked up wrong, you can
> (attempt) to power up your part of the grid during a failure, and
> kill people in the attempt.

Agreed.  You should have an electrician install the automatic transfer
switch along with the UPS.  If you are going to install a permanent
generator you will need to get permits anyway, which will require a
licensed electrican.  Talk to your UPS vendor for electrical contractor
recommendations in your area.

BTW, for safety and protection of your equipment, large automatic transfer
switches sense voltage, frequency, and phase when switching between
generator and utility power.

Mike.

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