AC Line filters?

[petteyg359]

The VA rating and W rating are definitely two very different properties, it sounds like you're trying to compare them though.

No, but I do find it really annoying since I have to read the specs on each one instead of just searching by model number. There are two models of the rack-mount UPS in my second link - one with 900 W / 1500 VA and one with 1500 W / 1500 VA. Both say "1500" in the model number. Clearly the VA rating is meaningless and they really need to stop using it for marketing since practically nothing is rated by VA instead of watts.

 

[ATMINSIDE]

No, but I do find it really annoying since I have to read the specs on each one instead of just searching by model number. There are two models of the rack-mount UPS in my second link - one with 900 W / 1500 VA and one with 1500 W / 1500 VA. Both say "1500" in the model number. Clearly the VA rating is meaningless and they really need to stop using it for marketing since practically nothing is rated by VA instead of watts.

The VA rating is NOT meaningless.

Please read through this link: http://www.power-solutions.com/watts-va
You'll see how easily you can overdraw a UPS by assuming W = VA.

 

[JrClocker]

They are not the same.

VA is closer to "active" power... It basically specifies the maximum current for an AC circuit.

Watts is "real" power.

Power_watts = Vrms * Irms * cos (theta)

Vrms = rms value of AC voltage
Irms = rms value of AC current
Theta = phase angle between Voltage and Current sine waves.

For highly capacitive loads, theta will be negative...-90 degrees for pure capacitive load (no real power, but lots of VA)

For highly inductive loads (like a power supply, refrigerator, anything with a motor, etc) theta will be positive...+90 degrees for pure inductive load (no real power, but plenty of VA)

 

[ATMINSIDE]

They are not the same.

VA is closer to "active" power... It basically specifies the maximum current for an AC circuit.

Watts is "real" power.

Power_watts = Vrms * Irms * cos (theta)

Vrms = rms value of AC voltage
Irms = rms value of AC current
Theta = phase angle between Voltage and Current sine waves.

For highly capacitive loads, theta will be negative...-90 degrees for pure capacitive load (no real power, but lots of VA)

For highly inductive loads (like a power supply, refrigerator, anything with a motor, etc) theta will be positive...+90 degrees for pure inductive load (no real power, but plenty of VA)

Note that very good modern PSU's are not a highly capacitive load as they use PFC instead of Caps for input power.
Older style and cheaper PSU's though are still highly capacitive.

 

[JrClocker]

Correct.

But PFC does not respond instantly to a change on the load of the power supply...there is a time lag, and this will make the VA at the power supply spike.

 

[ATMINSIDE]

Correct.

But PFC does not respond instantly to a change on the load of the power supply...there is a time lag, and this will make the VA at the power supply spike.

Not instantly, but pretty near to it. Enough so the power source can be considered virtually equal on VA and W.
You're looking at ~99% VA to W instead of ~60-70% VA to W.

 

[JrClocker]

Not instantly, but pretty near to it. Enough so the power source can be considered virtually equal on VA and W.
You're looking at ~99% VA to W instead of ~60-70% VA to W.

Don't make me bust out my oscilloscope!

 

[larrymoencurly]

I've seen only one model backup power supply not contain a line filter, an old 300VA Belkin (2 samples, completely different insides). I had my computer plugged into one socket of an AC wall outlet and a laser printer plugged into the other socket of the same outlet, and whenever the laser turned on, the computer would freeze or reboot. That never happened when I used any APC backup.

Your computer's power supply has a good line filter inside it, unless it's a junk brand PSU.

 

[Silver_Pharaoh]

Wow! Okay.

So Should I only be concerned with the UPS's wattage rating rather than it's VA rating?
I could probably hit 900 watts @ the wall..

@larry
Yes, indeed my PSU has PFC but I'm wondering if it's enough or if it's having a hard time filtering the 113v AC I get?

 

[ATMINSIDE]

Yes, watch the wattage rating, I'd stick to the same series you were planning on though.

 

[DNRDustin]

Wish I would have read this before started my own thread and making a purchase. Still thoroughly confused about VA. What did you decide on SP? I grabbed the cp1500pfclcd.

 

[Silver_Pharaoh]

Wish I would have read this before started my own thread and making a purchase. Still thoroughly confused about VA. What did you decide on SP? I grabbed the cp1500pfclcd.

I haven't made a choice yet actually....
It'll be from CyberPower though, they seem to get positive remarks.
Currently waiting on a Phenom II from a fellow member here so I can test drive a PHII before I buy a new CPU. It'll also be a test to see if I can attain the same overclock as he did. If not then I know something is up and that's when I'll know if I need to pick up a UPS asap.

Let me know what you think of it though when you do get it. Though I doubt you'll have any issues with it.

 

[ATMINSIDE]

As long as you're in this series you're going to get a seriously awesome unit.
https://www.cyberpowersystems.com/products/ups/pfc-sinewave/

I'd probably just go for the CP1500PFCLCD, do you really think you'll pull more than 900W with the desktop and server?

 

[Silver_Pharaoh]

As long as you're in this series you're going to get a seriously awesome unit.
https://www.cyberpowersystems.com/products/ups/pfc-sinewave/

I'd probably just go for the CP1500PFCLCD, do you really think you'll pull more than 900W with the desktop and server?

Not combined. No.
The server is currently on that APC ES650 UPS I have. The server is in the living room and my rig is in my room without a UPS right now.

I could probably get away with less actually. I've stopped folding on the CPU recently it's just the GTX780 folding now.


My issue right now is I need a new car very soon so I've been putting off any sort of unnecessary purchases lately so I don't want to buy one until I can confirm somehow that my power is infact dirty enough to cause poor overclocks and warrant purchasing one of these UPS's

 

[RJARRRPCGP]

Which is weird since I'm the 2nd on the street....


Apparently 113v is normal in Canada. At least that's what google is saying

We likely get our power from Canada, (except some stations) and my UPS usually measures 122 V to 127 V.

And the 110 V to 117 V range possibly means your house is connected to an ancient transformer...

It can mean the circuit your PC is connected to, is maxed out as well...

It does appear that lower voltages, such as 113 V are the norm with real old transformers. (talking more like the 1950s and the 1960s!)

I saw some houses in Vermont that looked like they're connected to an ancient transformer. (Especially if the transformers are black in color)

IIRC, 113 V is so low for today's standards that Jonny Guru uses that voltage to stress-test PSUs and check the worst-case power factor...

 

[Alaric]

Just for information , my measurements at the wall here run 127 ACV to 130 ACV.

 

[Silver_Pharaoh]

We likely get our power from Canada, (except some stations) and my UPS usually measures 122 V to 127 V.

And the 110 V to 117 V range possibly means your house is connected to an ancient transformer...

It can mean the circuit your PC is connected to, is maxed out as well...

It does appear that lower voltages, such as 113 V are the norm with real old transformers. (talking more like the 1950s and the 1960s!)

I saw some houses in Vermont that looked like they're connected to an ancient transformer. (Especially if the transformers are black in color)

IIRC, 113 V is so low for today's standards that Jonny Guru uses that voltage to stress-test PSUs and check the worst-case power factor...

House is about 19 years old. It could be that we are far away from a transformer station?
Maybe crappy wires underground. Light flicker here often remember...

Just for information , my measurements at the wall here run 127 ACV to 130 ACV.

Near me at all? (Central Ontario)

 

[dyckah]

Which is weird since I'm the 2nd on the street....


Apparently 113v is normal in Canada. At least that's what google is saying

sounds fishy to me.
i have had my UPS in a few different houses now, in various different outlets around the house, and voltage is almost always in the 118-122v range, never seen higher, and when it goes much lower than that, the battery backup clicks in, but that doesnt happen often. and im in a 100+ year old house with 30ish year old wiring, and my last place was from the late 60's with original wiring

Just for information , my measurements at the wall here run 127 ACV to 130 ACV.

wow thats high!

 

[Alaric]

Measured with an Extech multimeter in El Mirage , AZ. I've seen spikes as high as 132 ACV.

 

[dyckah]

Not combined. No.
The server is currently on that APC ES650 UPS I have. The server is in the living room and my rig is in my room without a UPS right now.

I could probably get away with less actually. I've stopped folding on the CPU recently it's just the GTX780 folding now.


My issue right now is I need a new car very soon so I've been putting off any sort of unnecessary purchases lately so I don't want to buy one until I can confirm somehow that my power is infact dirty enough to cause poor overclocks and warrant purchasing one of these UPS's

i know its somewhat unrealistic of a load, but my 8370 and 280x, while running heaven benchmark, and prime95, 8370 overclocked, 280x stock, will sometimes hit 800-850w from the wall. sorta hovers at around 800w, with odd spikes to nearly 850w

Measured with an Extech multimeter in El Mirage , AZ. I've seen spikes as high as 132 ACV.

crazy.
i thought that most appliances had operating voltage of 110-120v, at least a couple of the ones that i checked at home here are, other than the ones that are 110-240v operating range.