[Nut-upsuser] Slightly OT: Generators & UPS

[Aleksandr Derevianko]

Dan Mahoney, System Admin wrote:

> On Fri, 1 Sep 2006, Basheer Noorgat wrote:
>
> Actually we've been where I work of a similar but different issue.
>
> Power goes out. UPS catches load. Generator spins up. UPSes see 
> generator power and accept it, go back into standby.
>
> When the transfer switch kicks BACK (which is done WITHOUT a voltage 
> drop as we are switching from good-power to good-power), the UPS sees 
> it as a power LOSS situation and goes to battery, and subsequently 
> dies. Our powercom rep says that we need to upgrade because of this. 
> Has anyone else ever heard of an issue like this?
>
> Also, is there a better list for the discussion of general UPS-related 
> issues?


We are using a several model of huge UPS's, some of them with generator 
backup. Usually it depends upon of UPS settings.
For example, if generator frequency is slightly moving, UPS can decide 
what it can't protect load against manual bypass
with asyncronous phase. In such case, IPU can decide to use battery 
until it become empty.

Some UPS's can decide that input is bad if input is loosing too frequently.

All such cases can be avoided, just carefully read manual for you UPS 
and configure it accordingly.

-- 
С уважением,
Александр Деревянко