Answer / neha sharma

offline ups is least expensive whereas online ups most
expensive biggest.
offline ups typical transfer timeis 4m whereas online ups
no switching time.

Answer / venkatraman

An off-line UPS remains idle until a power failure occurs,
and then switches from utility power to its own power
source, almost instantaneously. An on-line UPS continuously
powers the protected load from its reserves (usually lead-
acid batteries or stored kinetic energy), while
simultaneously replenishing the reserves from the AC power.

The on-line type of UPS, in addition to providing
protection against complete failure of the utility supply,
provides protection against all common power problems, and
for this reason it is also known as a power conditioner and
a line conditioner.
Source(s):

Answer / pavail

online ups id expensive ,biggest and heaviest
offline ups is less expensive time

Answer / ankush dhiman

In online ups supply goes simutaneously to battery bank for
charging purpose and to apparatus(like pc, any machine) and
in offline ups firstly ac convert in dc and charge the
battery and then dc convret in ac and give to apparatus.

Answer / shiva shankar

The offline UPS is in standby mode. The charger is maintaining the battery, but the inverter stage is not running. Power goes from input to output, bypassing the inverter.
In this configuration, the charger and inverter design is less, as the charger is usually in trickle mode and the inverter does not need to run continuously. On power fail, the inverter starts up and takes the load. There is a glitch in output, a few line cycles, but most loads can handle this.
The online UPS runs all the time. The charger now runs the inverter, as well as maintaining charge on the battery. The inverter supplies the load. Power goes from input to charger to inverter to output.
In this configuration, the charger and inverter design is more, as they need to run continuously. On power fail, there is no glitch, because the inverter is already running and supplying the load. Usually, there is synchronization between the inverter and the line, so that failure of the inverter can initiate fall-back to the line without glitch.


Read more: http://wiki.answers.com/Q/What_is_the_Difference_between_off-line_and_online_UPS#ixzz1MJtsQvtb

Answer / raju

In ONLINE UPS, the load is always connected to
inverter output only in both the cases, whether normal
power supply is available or not.

In OFFLINE UPS, Inverter output is connected to load only
when normal AC power supply fails, means when AC power is
available it is directly goes to output.

Answer / p. gupta

in case of offline ups power is processed(step down or up to maintain specified voltage level and filtered) and fed to the load , in case of mains failure power is supplied by inverter
while in case of online ups inverter is always on to supply power to load. power from mains and inverter is synchronized and fed to load

Answer / baskar rajaraman

PLEASE ANYBODY TELL ME THE CORRECT AND CLEAR EXPLANATION

Answer / chandu

online ups is always in use offline ups works only when
there is a power cut

Answer / vinay srivastav

On line UPS gives out put through inverter card out put at
all time AC supply on or off. That means UPS always on and
gives AC out put which is converted from DC out put of
Battery voltage. But the Battery life in this type of UPS is
low as compare to that of offline UPS.

But offline UPS gives out put only when commercial supply is
off. commercial supply directly given to the load and when
commercial supply fails UPS feeds the supply to load. That
means UPS is not connected to load at all the time. In this
case battery is not connected all the time so the battery
life is more as compare to online UPS

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