UPS hold-up time...

[BillP]

Hi,
reading this PSUs roundup I'm curious to know the minimum hold-up time supported from my BR1500GI.
http://www.tomshardware.com/reviews/gaming-psu-efficiency,2796-26.html

[Anonymous user]

Sometimes they say 17ms, sometimes they say 16ms, but the actual time is one full 60Hz AC cycle which means, 16.6ms.

[Anonymous user]

UPSes usually change from AC to Battery power in less than 10ms.

[BillP]

nice to know, thanks 🙂

[BillP]

Smart UPS is typically 2-4ms, where as Back UPS are more like 6-8ms.

[BillP]

thanks angela.

[Anonymous user]

One thing that no manufacturer is clear about is if the transfer time available on the specs. sheet is the transfer time in miliseconds considering the time the UPS takes to analyze the sine wave anomally or if it is the relay reaction time only. The manufacturer of the relay model used on one of my UPSes say the typical operating time of it is about 8ms. Can the UPS analyze the sine wave is less than 2 ms so as to "decide" what measure will be taken?

[BillP]

FYI, I saw this yesterday for something else - typical transfer time on a Line Interactive Smart-UPS is 2-4ms at High Sensitivity. It will be longer at lower sensitivity settings and the quality of the input power will also affect this. A transfer time of 4ms is not anything we would consider to be out of spec. If anyone absolutely needs less than that, they may want to look into a Smart UPS RT or other UPS with 0ms transfer time.

Sensitivity comes into play with what rau is talking about how sensitive a UPS is to the incoming power and how long it takes to decide that there is a problem with the input power.

this may help -> http://nam-en.apc.com/app/answers/detail/a_id/62/

It may be a tiny bit different on the new SMX/SMT units since they are a different hardware platform.

[Anonymous user]

I was just asking out of curiosity because anything below 16.6ms should be fine for most computer PSUs although the longer it takes to transfer to battery, the bigger the PSU inrush current will be, but I'm sure the APC Back-ups line can transfer to battery power well below 16.6ms.

Computer PSUs should comply with the ATX standard and it states that all PSUs should withstand a 0 volt input for 16.6ms and @ full load, so at half load the PSUs can go without power for over 30ms. I don't know of anyone who runs its power supply @ full load 24/7 or even for a few hours because most computers come or are built with a PSU above its power needs so will never run @ full load even if you run the most hardware demanding peace of software. Despite of that, there are a few PSU units out there that are not complying with the ATX standards so if it can't withstand a 10ms of transfer time, the PSU manufacturer is the one to blame.

Thanks for the link to that article but I had already read this before.

[BillP]

thanks for the clarification.

[BillP · Accepted solution]

Hi,
reading this PSUs roundup I'm curious to know the minimum hold-up time supported from my BR1500GI.
http://www.tomshardware.com/reviews/gaming-psu-efficiency,2796-26.html