UPS's are used to protect against decreases in voltage (either blackouts or brownouts/sags) by switching over to battery power when it senses certain electrical problems.
(UPS's; are used; to protect against decreases in voltage (either blackouts or brownouts/sags) by switching over to battery power) (UPS's; to protect; against decreases in voltage) (UPS's; by switching over; to battery power; T:when it senses certain electrical problems) (it; senses; certain electrical problems)
UPS's UPS's UPS's it
are used to protect by switching over senses
to protect against decreases in voltage (either blackouts or brownouts/sags) by switching over to battery power
against decreases in voltage
to battery power T:when it senses certain electrical problems
certain electrical problems