coulter said:
Are you saying that ZSNH give rise to currents that flow into one conductor and do not come back on the others of that circuit. I don't know how that could happen. Kirchoff and Norton kind of get in the road.
An earlier
diolog with Fluke tech. support describes how their 337 clamp probe Hz function measures neutral harmonics only if zero-sequence sums, found in the nuetral, are the predominate magnitude (ie) 180Hz. The clamp only shows 50/60Hz on phases, since pos. & neg. sequences don't add the same way.
Regarding using your clamp-on ammeter around conduit, if it has a Hz function that reads > 50/60 hz there are harmonics. A reading of 180 Hz shows the presence of triplen sums (3rd harmonics). AKA Zero-Sequence Neutral Harmonics (ZSNH) for others who read this.
If you noticed high Hz while uisng a clamp around conduit, let us know. I've never seen it done, much less from grounded-Delta secondaries, but apparantly you would know it, if the Hz show it.