fast switching low voltage detector.

[TheElectron707]

I am having a problem in my custom made UPS, that if the mains
switches off and on very very rapidly the UPS cannot sustain/detect it
and the computer attached to it gets restarted.

can any one plz guide me to a circuit that could detect the fast
switching of mains ( may be by seeing sensing the droping rms voltage
of mains, within micro seconds) and send a corresponding signal to the
ups circuit before hand to switch OFF.

any help will be much appreciated.

 

[Ian Stirling]

I am having a problem in my custom made UPS, that if the mains
switches off and on very very rapidly the UPS cannot sustain/detect it
and the computer attached to it gets restarted.

can any one plz guide me to a circuit that could detect the fast
switching of mains ( may be by seeing sensing the droping rms voltage
of mains, within micro seconds) and send a corresponding signal to the
ups circuit before hand to switch OFF.

You dfon'ty need microsewconds.
The conputer can handle at least 10ms, without problems.
How is your AC generator switched on and off, and how do you now sense it?

 

[Tweetldee]

I am having a problem in my custom made UPS, that if the mains
switches off and on very very rapidly the UPS cannot sustain/detect it
and the computer attached to it gets restarted.

can any one plz guide me to a circuit that could detect the fast
switching of mains ( may be by seeing sensing the droping rms voltage
of mains, within micro seconds) and send a corresponding signal to the
ups circuit before hand to switch OFF.

any help will be much appreciated.

Your UPS should detect that the mains have dropped within one half cycle,
that is, within 8.3 ms. The power supply in the computer should be able to
handle that small a dropout. The UPS generator then switches on to take
over the load. The UPS stays on for a minimum fixed time (e.g., 5 seconds),
monitoring the mains for stability. When the mains have stabilized and
remains stable for a few seconds the UPS generator shuts down and switches
back to the mains. It's called hysteresis.
This technique avoids the brownout condition, where the mains voltage is
marginal, fluctuating around the trip point of the UPS.
Cheers!
--
Tweetldee
Tweetldee at att dot net (Just subsitute the appropriate characters in the
address)

Time is what keeps everything from happening all at once.