UPS incompatible with PFC??

[drjones]

Hi, this is all new to me...I'm learning that certain computers and servers may be built with power supplies that have PFC technology, which can be incompatible with most lower-end battery backups.

Apparently, what will happen is if the PC/server has PFC and the battery backup does not support it, the computer will just shut off when the power goes out, even if the battery backup is otherwise working properly.

Is this a real issue, and if so, what brand/model of UPS do you recommend to work with PFC, particularly for servers?

Thanks

 

[coffee]

I have not ever heard of this before.

Normally you will use a serial or USB cable and connect the UPS to the server/computer and when the battery threshold reaches a certain point the shutdown command is issued to the server/computer. Its all basically software driven.

On my server running linux it will shutdown when 90 percent of the power is exhausted.

The only issues I have seen are poorly written drivers from low end UPS units. I would think that if you stick with a reputable name like APC you shouldnt have any issues.

----------------------------------------------------------- below added/edited again:
This link below talks a bit about the issue. It seems to be related to an out of phase AC power source that will trick a computer with a poor power supply to shutdown "instead of dealing with the problem".

To be honest, I have never ran into an issue with this in all my years of computers. But Im not saying it doesnt happen though.

http://www.howtofixcomputers.com/fo...on-laptops-modified-sine-wave-ups-303978.html

Best Regards,

coffee

 

[phaZed]

While I can't help you with purchasing a UPS, I can shed light on the problem.

The problem is that UPS's do not (Generally) Produce a very good sine-wave.. rather it is usually a jagged-square-wave because the UPS has to produce a "fake" AC signal from DC batteries. A better UPS will produce a better wave.

PFC enabled PSUs actively monitor the load on the DC side and attempts to "align" or sync the waveform to the AC side. The closer you are to being in-phase with the AC wave form the more efficient you are and reactive power(loss) is as close to 0 as possible.
So, if your UPS's output wave form is not very good or fluctuates wildly you can see how a PFC PSU may not work well or go into a self-protection mode.

You need a UPS that has a feature marketed as "Pure Sine wave".

 

[tek9]

I believe the APC Smart UPS line is Pure Sine Wave, as opposed to their cheaper Back-UPS line.

 

[drjones]

I believe the APC Smart UPS line is Pure Sine Wave, as opposed to their cheaper Back-UPS line.

Yes, I think this is correct...unfortunately they seem to be a lot more expensive, but oh well....

Can anyone shed any light as to which makes/models of computers/servers would have PFC-enabled power supplies, or do we have to now manually check??

 

[EvolutionElectronics]

we had this issue with a doctors office we setup before, when the power went out the fans on the servers would kick into full speed and stay there even after the power was restored, it had to do with the sine waves as well. they were triplite 1500's though

 

[ComputerRepairTech]

I have cheapy cyberpower UPS's on my computers which have active PFC power supplies (like pretty much all of them these days). They are all corsair power supplies.

95% of the time when power goes out its fine, the other 5% it will lose power...seems like the longer the power flickers before going out the more chances of the pc shutting off.

 

[YeOldeStonecat]

Yes, I think this is correct...unfortunately they seem to be a lot more expensive, but oh well....

Can anyone shed any light as to which makes/models of computers/servers would have PFC-enabled power supplies, or do we have to now manually check??

For our clients servers...we stick with UPS units which are designed for....servers!!! And that means Smart UPS models from APC.

We stick with APC as our brand of choice, quality units, and the company is local..(45 minutes away from me..they are in Rhode Island) so we're supporting the local economy.

I've seen other brand power supplies not work well with clients servers. And naturally when I see desktop grade UPS units ...including APC Back Ups models, used on servers...the clients servers suffer.

I'm a believer in using the appropriate equipment to support things like servers, and if that means using Smart UPS..which are more expensive, so be it! Stability and integrity of the clients data is the most important thing here....a business relies on their server(s).

 

[angry_geek]

I'm with stoney on this. In our own data center, I also have a bank of capacitors and voltage regulators before the UPS units. Whether it's storming, the HVAC kicks on, brown out, generator running, no matter what, I have a nice steady 115 volts. You can do this for a single server with an apc voltage regulator. About $40. Then plug in your UPS. I still use the good UPS units with built in avr, but I feel warm and fuzzy inside with that additional regulator.

 

[drjones]

For our clients servers...we stick with UPS units which are designed for....servers!!! And that means Smart UPS models from APC.

We stick with APC as our brand of choice, quality units, and the company is local..(45 minutes away from me..they are in Rhode Island) so we're supporting the local economy.

I've seen other brand power supplies not work well with clients servers. And naturally when I see desktop grade UPS units ...including APC Back Ups models, used on servers...the clients servers suffer.

I'm a believer in using the appropriate equipment to support things like servers, and if that means using Smart UPS..which are more expensive, so be it! Stability and integrity of the clients data is the most important thing here....a business relies on their server(s).

Yes you're right. SmartUPS it is!