I'm talking about ulimited power supplies designed to protect computers from power cuts and keep them running without resetting. It is known that non sinewave UPSes don't react in time to the power cuts and the computers turn off.
I've been reading conflicting reports on this issue. Some seem to indicate that a stepped sinewave, which is similar but not quite pure, is enough to feed a PFC power supply, while others say that the sinewave has to be pure? Which is it?
Pure or Adapted sine-wave are the two that have worked for me.
I had issues after a PSU upgrade to an active PFC PSU. When I inquired with Cyberpower about my issues (hadn't had any before and I live on a very unstable power grid), here is their reply
"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.
For computer systems using power supplies with Active PFC, we recommend that you protect your equipment with a UPS that provides pure sine wave output or Adaptive Sinewave output – CyberPower’s newest UPS product line. We make a full line of Adaptive Sinewave and Pure Sine UPS models that meet most technical and pricing requirements.