Does Line-interactive UPS support PSU with PFC?

[BUlly_boy_2101]

I am thinking to buy a new ups for my new corsair rm650 psu. i learned that this psu has something known as the PFC with basically protects other components from a bad current. so i decided to buy a ups with pure sine wave technology but since it is too expensive so i decided to go for the less expensive Line interactive form....but the main question here is whether my psu( PFC activated) is going to support this line interactive ups( which has Stepped Approximation To A Sinewave)........PLEASE HELP!!!

 

[bigpinkdragon286]

First off, let's clarify that Line-Interactive and True Sine Wave Output are unrelated features of a UPS. Line-interactive is how the UPS deals with irregularities on the AC input, whereas stepped / simulated or true sine wave deals with the waveform shape of the voltage output. 🙂

If your power supply has Active PFC, you are better off spending the extra on the UPS with true sine wave output if you want a guarantee of compatibility. Some power supplies with active PFC tolerate the stepped sine wave, some do not. The only way to know for sure is if the PSU in question has been tested with a stepped sine wave by somebody willing, or if you're good at electrical engineering and know enough about the design of your equipment, which I'm going to say is not the case or you wouldn't be here.

If you wish to avoid potentially overloading the UPS, you need to size it larger than the maximum input power of the power supply, which should be approximately 1.25 x the active PFC PSU's total rated output power (1.25 is for a typical 80+ Certified PSU, and will give you a good safety margin). So, an appropriately sized UPS for your 650 watt Gold (87%) rated PSU would need to be able to handle in the neighborhood of 750 watts of actual power output, or you'll likely find the UPS will reset or simply power down during the transition to battery if the PSU is under any significant form of load.

Properly sizing the UPS to the PSU still doesn't answer your initial question of, will your PSU work with the stepped sine wave. I can't answer that. I would honestly want to test the PSU on a stepped sine wave before saying one way or the other. It may work fine. You may also find it only works when the PSU is not loaded. And you may end up finding that there are undesirable consequences such as damage to the PSU if used long term.

Here is part of an email I ran across from Cyberpower, a UPS manufacturer:

"Your computer uses a power supply that utilizes Active Power Factor Correction (Active PFC) to improve efficiency. Power supplies with active PFC may experience incompatibility problems with a UPS that does not provide pure sine wave power output when the power supply switches from AC power to UPS battery power. As a result, when a computer system using a power supply with active PFC is attached to a non-sine wave UPS, the system may shut down when it switches to battery power. Also, if the power supply continues to operate, it may produce a humming or high pitch noise while running on battery. This humming indicates the power supply is operating beyond specified tolerances and may damage the power supply."

 

[BUlly_boy_2101]

First off, let's clarify that Line-Interactive and True Sine Wave Output are unrelated features of a UPS. Line-interactive is how the UPS deals with irregularities on the AC input, whereas stepped / simulated or true sine wave deals with the waveform shape of the voltage output. 🙂

If your power supply has Active PFC, you are better off spending the extra on the UPS with true sine wave output if you want a guarantee of compatibility. Some power supplies with active PFC tolerate the stepped sine wave, some do not. The only way to know for sure is if the PSU in question has been tested with a stepped sine wave by somebody willing, or if you're good at electrical engineering and know enough about the design of your equipment, which I'm going to say is not the case or you wouldn't be here.

If you wish to avoid potentially overloading the UPS, you need to size it larger than the maximum input power of the power supply, which should be approximately 1.25 x the active PFC PSU's total rated output power (1.25 is for a typical 80+ Certified PSU, and will give you a good safety margin). So, an appropriately sized UPS for your 650 watt Gold (87%) rated PSU would need to be able to handle in the neighborhood of 750 watts of actual power output, or you'll likely find the UPS will reset or simply power down during the transition to battery if the PSU is under any significant form of load.

Properly sizing the UPS to the PSU still doesn't answer your initial question of, will your PSU work with the stepped sine wave. I can't answer that. I would honestly want to test the PSU on a stepped sine wave before saying one way or the other. It may work fine. You may also find it only works when the PSU is not loaded. And you may end up finding that there are undesirable consequences such as damage to the PSU if used long term.

Here is part of an email I ran across from Cyberpower, a UPS manufacturer:

"Your computer uses a power supply that utilizes Active Power Factor Correction (Active PFC) to improve efficiency. Power supplies with active PFC may experience incompatibility problems with a UPS that does not provide pure sine wave power output when the power supply switches from AC power to UPS battery power. As a result, when a computer system using a power supply with active PFC is attached to a non-sine wave UPS, the system may shut down when it switches to battery power. Also, if the power supply continues to operate, it may produce a humming or high pitch noise while running on battery. This humming indicates the power supply is operating beyond specified tolerances and may damage the power supply."

I can't spend big bucks for a pure sine wave ups....so I think I must go for a 1.5kva ups with stepped approximation of a sinewave..... I just want to know whether it will seriously affect my PC or whether the issues will be minor?