Field measurement of harmonic distortion- how?

Jun 27, 2021 3 Replies

My son has a new welder, spec'd 5% max THD input AC power. I see Keysight has a DMM with a "relative distortion" position. Anyone used one of these? Useful? Anyone have a favorite, or a simple method? Cheers


Wond wrote: =============

** The welder is clearly not happy with power from a "modified square wave" DC inverter. So don't use one.

Regular mains power is gonna be fine.

..... Phil

My thinking too, but it appears from available bumf that inverter types claim less THD than cheap conventional gens. It would be interesting to see how Agilent/Keysight measure it in their DMM. Thanks for reply.

Wond wrote: ==============

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** Oh dear - FYI a "DC inverter " runs off a 12 or 24V battery.

" Inverter generators " are pure sine wave. The AC supply has a few percent of 3rd and 5th harmonics.

** For sure. I saw nothing on the Agilent site about it.

Can you borrow a scope to take a peek at the wave?

.... Phil

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