DC Load Regulation and AC Ripple
DC Output Load Regulation
To simulate real world and maximum loading conditions, the be quiet! Straight Power 10 800W CM power supply was connected to the load testers and supplied with a constant 115 VAC. In this test we are interested in seeing how well a PSU can maintain the various output voltages while operating under different loads.
The ATX12V V2.2 tolerance for voltages states how much each output (rail) is allowed to fluctuate and has tighter tolerances now for the +12V outputs. I have also included a second table of expanded tolerances (±1% to ±6%) for reference.
The following tables list the DC voltage results for the PSU while operating on 115 VAC, 60 Hz.
The Straight Power 10 800W CM power supply produced very good voltage regulation on all of the DC outputs while delivering the full rated 800 watts total load. All of the critical rails stayed within ±2%, which meets be quiets!’s claims for this PSU.
AC Ripple and Noise on the DC Outputs
The amount of AC ripple and noise present on the DC outputs was checked using a digital oscilloscope. This AC component may be present in the KHz range where most switching power supplies operate or it may be more prevalent at the 60 Hz line frequency. We adjust the O-scope time base to look for AC ripple at both low and high frequencies. The ATX12V V2.2 specification for DC output noise/ripple is defined in the ATX12V Power Supply Design Guide.
Ideally we would like to see no AC ripple (repetitive) or noise (random) on the DC outputs – the cleaner the better! But in reality there will always be some present. I measured the amplitude of the AC signal (in millivolts, peak-to-peak) to see how well the power supply complied with the ATX standard. The following table lists the ripple/noise results during all of the load tests for the main output voltages of interest.
The Straight Power 10 800W CM power supply starts out OK but then all of the outputs start to develop more ripple and noise spikes than we would ideally like to see, especially the +12V output. However, all the values stayed under the recommended ATX guidelines.
Lee at least now people got a
Lee at least now people got a matching PSU for the Be Quiet “case, heat sink, and fans”.
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To simulate real world
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To simulate real world operation, some of the warm exhaust air from the PSU under test is recirculated back to the intake through a passive air duct, which allows the PSU air inlet temperature to increase with load, just like it would in a real PC.
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This is not true in many cases, such as when the PSU is at the bottom of the case and when the case uses a rotated design like the Silverstone FT02 and FT05.
Yes, you are correct in many
Yes, you are correct in many instances. Maybe a better wording would be "to simulate worst case, real world operation…
You disappeared again.
You disappeared again.