Electronics > Beginners
Oscilloscope for AC work ?
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SND:
I need a good safe way to check harmonics, THD and wave form on 120 and 240V  1ph 60hz circuit, with possibly up to 125A/1ph breaker on them. I expect the main harmonic to be about 5khz but there could be other stuff in there, higher or lower.(IGBT/VFD's)   Most of this will be done at the panel, and input of a few units.

I may like to be able to check some 3phase 60hz wave form as well and what harmonics might be going on there but its less important.
I can probably stick to just doing each leg to ground on their own but if its possible to go leg to leg then great. I'm still reading/learning about what these oscilloscopes can/can't do, but I do well know the dangers of the electricity I'm dealing with

Would the Siglent SDS1202X-E or SDS1104X-E be a good choice for this application?  Are the probes that come with it ok for this? I see they're just 10x probes. Should they be upgraded to something else and if so, which?
I also read a bit into the Hantek DSO-8060 handheld unit, looks interesting but I'm not sure if that's a better or worse choice.
I want something reliable and accurate enough that will last many years as I will need to check the THD levels periodically.

Are there any other units and accessories perhaps better suited for this that you'd recommend?

thanks
DDunfield:
Any time you want to scope mains (especially across phases) you don't want to use a typical grounded scope.

I would recommend battery powered scopemeter certified for the voltages and type of circuits you will be connecting to.

Exactly which one to recommend depends on your budget and needs. Do you need more one channel?  Do you need advanced math FFT etc. Ability to upload waveforms to PC for analysis?
Fluke has some very nice offerings including a specialized "motor driver analyzer" series with harmonic measurements etc. -- warning - they're not cheap!

Dave
woodchips:
Look for a Powerscope, I have an 881 Mk2.

These are made in Australia and are specifically intended for AC mains power work, 400V input on all channels.

They are now old and quite rare, download a copy of the manual to see what it does.

Jwillis:
Another way is to use a 100:1 probe or High Voltage Differential Probe.All depends or how high a voltage you intend on scoping.Running your scope from an isolation transformer might  be a good idea .Maybe someone could comment on that idea.
bdunham7:
Is this a utility-fed mains circuit?  Or some type of generator/solar system?  Where is a 5KHz 'harmonic' coming from?

You need specialized equipment to do this safely.  My choice would be some flavor of Fluke Scopemeter, especially since they often come with excellent leads and probes.  There's no call for poking around in utility panels with cheap (or even expensive) regular oscilloscopes and their related probes.  There's just too many things that can go way wrong way too fast.
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