Ever wondered how a “high-efficiency” motor can start wasting energy and damaging bearings before it’s even been switched on?

We did too. So we tested it.

Using offline motor circuit analysis alongside online motor current signature analysis, we inspected brand-new IE4 motors still sitting in their crates. What we found changed the conversation completely. Critical impedance imbalance straight out of the box. One motor already showing early winding defects before it ever saw load.

That’s the moment labels stop mattering and evidence takes over.

This episode walks through why pairing de-energised and energised testing matters.

Offline MCA tells us what’s happening in the windings – contamination, resistive imbalance, insulation condition. Online MCSA, sampled at 44 kHz with serious resolution, shows us what vibration often can’t: rotor bar issues, air-gap problems, electrical harmonics, inverter-driven bearing currents.

In difficult environments – noisy plants, submersible pumps, generators, limited access assets – current signature analysis often gives cleaner, more repeatable insight than vibration alone. We’re seeing faults that used to hide in the noise.

And this isn’t theory. Across 750+ motors tested in the field, we see a clear link between impedance imbalance and winding health:

• <5% – normal
 • 5–8% – defect initiation
 • 8–15% – accelerated damage
 • >15% – critical

That gives teams something powerful: defensible alarm limits and a simple acceptance test that stops bad assets entering the plant.

There’s a practical win too. On one motor we reduced resistive imbalance from over 30% down to around 3.8% just by cleaning and correctly torquing the terminations. Test. Fix. Retest. Immediate improvement.

The real gains come when sites take this seriously:
 Acceptance testing written into purchase orders.
 Evidence required from the factory.
 Faults confirmed using at least two technologies.

That’s how you reduce energy loss, prevent shaft currents from destroying bearings, and turn condition monitoring into real reliability improvements – not reports that sit on a shelf.

If uptime matters.
 If energy efficiency matters.
 If you want better decisions with less noise and less drama.

This episode shows the path: measure what matters, set your own standards, verify the fix, and keep learning.

Enjoy the episode.
 If it helps you rethink your motor strategy, subscribe, share it with a teammate, and drop a quick review with your biggest testing win or surprise.

Support the show