[asterisk-biz] backup power requirements for emergency calling

[alex at pilosoft.com]

On Fri, 14 Apr 2006, Andrew Kohlsmith wrote:

> On Friday 14 April 2006 14:18, calvis wrote:
> > Takes 20 minutes for a generator to kick in?  Sounds like you need an
> > automatic transfer switch.  My generator kicks in 20 seconds after a
> > power outage with an automatic transfer switch.
> 
> Generally speaking you don't *want* your generator to kick in like that.  
> You want to ride out with UPS/battery until you've experienced a 20-30
> minute outage, at which point the outage is likely going to be a lengthy
> one and THEN you want to start up the generator.
This is why asterisk guys should stick to doing asterisk, and leave 
facility management to people who know that.

> It's very common to do things this way, as generators aren't something
> that really appreciate being cycled.
No, it is not. You want your genset to start within 30 seconds after power
goes out. If it doesn't start, you might have 20-30 minutes to correct the
problem before UPS battery goes kaput.

Also, note that 20-30 minutes runtime is about average for a facility UPS.  
So, you *definitely* do not want to drain the battery to the end before
starting genset.

-alex