Test Setup/Equipment
When testing a power supply, the most important factors that need to be considered are the ability to isolate the unit from environmental factors and the ability to produce consistent, and repeatable, results in a controlled environment. Otherwise, there is no legitimate way to compare the numbers produced by one unit with those produced by another unit. Thus, the removal of confounding factors (introduced by the variability of the operating environment) is what we focus on in the basic testing setup that follows.
Incoming Power
In our power supply reviews, we start this process with the incoming power. The equipment used here includes:
- Tripp-Lite LCR2400 Line Conditioner
- The Tripp-Lite LCR2400 provides Automatic Voltage Regulation (AVR), AC surge suppression, and EMI/RFI filtering. The LCR2400 has a rated AC surge suppression of 1440 joules and a rated EMI/RFI AC noise suppression of 75 dB. The AVR settings on the LCR2400 allow for nominal operational output (120v) at an input voltage range between 89v to 147v by trimming output voltage by 9.6% when the voltage is between 128v and 147v, boosting output voltage by 8.9% when the input voltage is between 103 and 110v, and boosting output voltage by input voltages by 18.8% when between 89v and 103v.
- Staco 3PN2210B Variable AC Transformer (Variac)
- The Staco 3PN2210B is used to adjust the input voltage that our PSU “sees” anywhere from 0v to 140v from the 115v/120v nominal that is standard in North America.
- Extech 380803 True RMS Power Analyzer Datalogger
- The Extech Power Analyzer is used to read our power draw on the AC side of our testing to give us half of the measurements we need in order to determine efficiency. It also provides the Power Factor (PF) readings in our reviews. The PF is the the ratio of real power (kW) to apparent power (kVA).
Testing Temperature
Following the incoming power portion, we continue to control our environmental and input parameters by addressing our testing temperature. The equipment used to control our temperature settings include:
- Quincy Labs 10-140 Incubator
- The Quincy Labs 10-140 incubator allows us finer temperature control and adjustment, in a reliable and reproducible manner from test to test, than what is possible in PC case. The incubator has a set temperature range of 15C to 62C (with a minimum temperature of 1C above ambient temperature) and will hold that temperature +/- 1C indefinitely. The incubator has been modified to vent the exhaust out the back of the incubator to not endlessly build heat inside the incubator.
- Sperry DT-506 4 Channel Digital Thermometer
- The Sperry DT-506 uses type K thermocouples to monitor temperatures between -50C and 1000C at +/-(0.3% +1C). This multichannel thermometer is used to monitor both intake temperature and exhaust temperature on the PSU simultaneously.
Load Testing
We next move on to the actual load testing portion of our power supply reviews. The equipment used for our actual load testing includes:
- SunMoon SM-8800 ATE Load Tester and SM-220 Electronic Load
- The SunMoon SM-8800 ATE and SM-220 Electronic Load form the core of our programmable load testing capabilities. In general, our reviews report the load (amperage) and output (voltage) on the 3.3v, 5v, +5vsb, and 12v rails. We will not be testing, or reporting, the -5v as it has been dropped from the ATX specification as of the ATX12v2.0 revision.
- Nautilus Integration PSTT-1 Transient Load Tester
- The PSTT-1 is a standalone unit that is responsible for transiently loading power supplies with an additional 9.25A on the 12v rail and an additional 3.75A on the 5v rail when triggered. The transient load duration on the unit is selectable between 10ms, 100ms, and 1s.
- USB Instruments DS1M12 Digital Oscilloscope
- The USB Instruments DS1M12 Digital Oscilloscope provides all the functionality of older CRT/LCD oscilloscopes in a smaller PC-based Oscilloscope. The DS1M12 has its own analogue-to-digital converter that directly interfaces, via a USB connection, with our PC. The oscilloscope connects to both the SunMoon SM-8800 waveform output and the Nautilus Integration PSTT-1 via BNC connectors. Data passed to the oscilloscope is visualized using the EasyScope II software bundle.