when the UPS backup power kick in...

[evyosh]

i recently got a brand new UPS because we have some power cuts time to time...

when suddenly the power goes and the UPS kick in only one of my monitors go off... this the video i made replicating the power cut buy unpluging the wall socket switch....

https://www.youtube.com/watch?v=a3NBKpJXbJQ

only the 1st monitor has this problem....
i thought this was a UPS issue.. and the UPS has 3 power outputs. so i change the sockets but same issue with the same monitor. i thought it was a problem with my cable and i changed power cables. still the same issue only on the 1st monitor..

what is this issue? this is a philips 200V 20inch monitor

 

[Rookie_MIB]

Could be an internal design issue with the power supply with the monitor. If you look at a PSU for a computer, when there's a minor power blink, the ATX spec has a 'minimum holdup time' where some large bulk capacitors have enough reserve capacity to keep the power 'on' during a minor blink like this. That holdup time is 16ms.

Now, depending on how the power supply in the monitor is made, and the time that the UPS takes to actually switch power over to battery (which is NOT instantaneous as relays have to switch over), if the monitor PSU doesn't have enough reserve capacity (or any reserve capacity!) to handle the switchover time then the monitor will shut off. Then power comes back 'on', and the monitor turns back on as it appears to do in the video.

 

[evyosh]

Could be an internal design issue with the power supply with the monitor. If you look at a PSU for a computer, when there's a minor power blink, the ATX spec has a 'minimum holdup time' where some large bulk capacitors have enough reserve capacity to keep the power 'on' during a minor blink like this. That holdup time is 16ms.

Now, depending on how the power supply in the monitor is made, and the time that the UPS takes to actually switch power over to battery (which is NOT instantaneous as relays have to switch over), if the monitor PSU doesn't have enough reserve capacity (or any reserve capacity!) to handle the switchover time then the monitor will shut off. Then power comes back 'on', and the monitor turns back on as it appears to do in the video.

both my monitors are the same... so then this is a monitor issue? will this be a issue in the future because the monitors are still less than 1 month old....

 

[evyosh]

UPS takes to actually switch power over to battery (which is NOT instantaneous as relays have to switch over), .

this what you said.. are there 100% no drop UPS? or everything has a drop?

 

[Rookie_MIB]

both my monitors are the same... so then this is a monitor issue? will this be a issue in the future because the monitors are still less than 1 month old....

Hmmm.. .didn't notice that. Just re-read it, and you switched outlets so it's not the outlet. The power supplies are internal to the monitor so it's not a power brick issue that you could swap out. As for an 'instant switch' UPS, they don't make them. Every UPS will have a relay as you -have- to switch large amounts of current over from the mains to the battery.

I have an APC server grade system - APC 1500 Smart UPS - with two additional battery carriers which will power my three servers, one desktop and two monitors with associated hardware (cable modem, switches, routers) for 6 hours. Yeah, it's a big beastie of a system. Still, it has relays and takes a split second to switch over.

About the only thing I can say is perhaps there's a bad capacitor in the PSU for the monitor - it happens - they can go bad depending on the age of the monitor - it looks like these were released a few years ago...

 

[evyosh]

Thank you So much for your help on this issue... i will contact the shop where i got these monitors... you are the hero @Rookie_MIB.. thank you so much again..

 

[InvalidError]

are there 100% no drop UPS? or everything has a drop?

Relays take 5-10ms to switch. The only UPS that have no switch-over delay are double-conversion or 'online' UPS which are always on: all input power gets converted from AC to battery-voltage DC, then back from DC to AC.

Online UPSes are considerably more expensive and the double conversion process introduces a significant waste of power.

 

[evyosh]

are there 100% no drop UPS? or everything has a drop?

Relays take 5-10ms to switch. The only UPS that have no switch-over delay are double-conversion or 'online' UPS which are always on: all input power gets converted from AC to battery-voltage DC, then back from DC to AC.

Online UPSes are considerably more expensive and the double conversion process introduces a significant waste of power.

wow got it.. i never had idea about this UPS stuff before.. and i asked the shop guys so many times.. they lied and lied.. that there are no relay time lol...