Measuring UPS/PPS Transfer Time and Power Quality - Page 1
Forum section: electronics / testgear

author: AdriftAtlas
author_rank: Contributor
timestamp: October 05, 2024, 06:22:10 am
content: I've been interested in portable power stations of late and have a few of them. I want to test how clean they are for computers and other sensitive electronics. Specifically, I want to measure transfer time from mains to inverter, frequency, voltage, any sort of distortion.In my research I found that I need to get a ground isolated oscilloscope (battery operated) and a high voltage differential probe. Using an attenuator alone is risky as I cannot trust that a power station has ground and/or neutral wired correctly.I've been considering getting an OWON HDS2202S and a Micsig DP10013 (now DP1500).Thing is that the Micsig has a 50x and 500x attenuation factor. The OWON supports 1x, 10x, 100x, 1000x, and 10000x. Everything I read says it doesn't support a custom factor.So if I start measuring 120VAC am I correct to assume I'll see 60VAC on the OWON if I set it to 100x and the Micsig at 50x? Is there any way for this scope to use a custom factor?Micsig also produces the DP3000 which has a 100x and 1000x factor but it's a lot more expensive and apparently more noisy. The discontinued DP10007 has 10x and 100x factors but it likely is hard to find.I've also been looking at benchtop scopes like the Siglent SDS1202X-E but I'm not a fan of its size nor its grounding.Capturing the transfer (power loss) is also tricky it appears depending on the scope. I see people using low voltage DC adapters that they feed into a second channel to capture the exact moment when the cut occurs. Is there a cleaner way?Is there another portable battery powered scope and differential probe combo that would be a good fit for me?

author: Someone
author_rank: Super Contributor
timestamp: October 05, 2024, 06:35:51 am
content: Quote from: AdriftAtlas on October 05, 2024, 06:22:10 amOnly one of those is needed, not both. Generally most people will recommend using an earthed oscilloscope and a differential probe as the "safest" choice. Or a fully isolated scope (industrial type) that has zero exposed metal. Floated scopes that have normal non-isolated channels and probes that assume there will be no hazardous voltages are the opposite of safe.Quote from: AdriftAtlas on October 05, 2024, 06:22:10 amOther way around. Probe divides the figure, and the scope multiplies. So (120 / 50) * 100 = 240Quote from: AdriftAtlas on October 05, 2024, 06:22:10 am"transfer " is not a term I'm familiar with, but if you want to measure power loss that requires voltage and current measurement at both input and output. Quite a bit more involved and complicated.

author: tautech
author_rank: Super Contributor
timestamp: October 05, 2024, 06:54:15 am
content: Quote from: Someone on October 05, 2024, 06:35:51 amOnly in the additional probes that are required for Efficiency measurements and the requirement of a 4ch DSO.SDS814X HD connection guide screenshot attached for Efficiency measurements in the Power Analysis mode.

author: AdriftAtlas
author_rank: Contributor
timestamp: October 05, 2024, 06:56:06 am
content: By transfer time I mean the interval at which there is no power e.g. the sine wave is distorted and/or RMS voltage is falling.Apparently I can't math today. 🤦‍♂️ Yes, it'd be 240VAC and not 60VAC with those factors.