Electrical Signature Analysis
One signal. Full drivetrain visibility.
Every AC motor draws current and voltage in patterns that reflect the mechanical condition of the full drivetrain — motor, coupling, gearbox, and driven load. Electrical Signature Analysis reads those patterns from the motor control cabinet. No sensors on the asset. No physical access required.
At Schiphol Airport, SAM4 detected 9 out of 9 developing faults — including bearing damage that the existing vibration programme missed. Read the case study →
The science
How a motor's electrical signature reveals drivetrain condition
ESA works because the motor's electrical supply and mechanical load are physically coupled. Every fault in the drivetrain — from bearing wear to cavitation — creates a measurable change in the electrical signature at the MCC.
A degrading bearing changes the air gap. A blocked impeller shifts the torque profile. A misaligned coupling creates periodic load oscillations. All of these appear as patterns in the current and voltage signals captured by CTs and VTs clamped at the motor control cabinet.
AI models — trained on data from over 10,000 industrial assets — compare each motor's signature against known fault patterns and its own baseline behaviour. The result: continuous condition monitoring for every connected drivetrain, without a single sensor on the asset.
The science is only half the story
ESA captures the signal. AI identifies the anomaly. But every alert is reviewed by a Samotics reliability engineer before it reaches your team. They confirm fault type, assess severity, and recommend a specific action. Time-critical alerts are escalated immediately.
See the full service model →Detection capability
What ESA detects across the drivetrain
ESA detects faults across the full drivetrain — weeks to months before failure. The matrix below maps fault types to equipment categories, with detection confidence based on over 10,000 monitored assets.
| Fault type | AC Motors | Pumps | Fans | Gearboxes | Compressors |
|---|---|---|---|---|---|
| Bearing degradation | ✓ | ✓ | ✓ | ✓ | ✓ |
| Misalignment | ✓ | ✓ | ✓ | ✓ | ✓ |
| Imbalance | ✓ | ✓ | ✓ | ● | ✓ |
| Cavitation | — | ✓ | — | — | — |
| Clogging / blockage | — | ✓ | ● | — | — |
| Electrical faults | ✓ | ✓ | ✓ | — | ✓ |
| Process deviations | ● | ✓ | ● | ● | ✓ |
| Efficiency degradation | ✓ | ✓ | ✓ | ● | ● |
This matrix is non-exhaustive. ESA can detect additional fault types depending on asset configuration and operating conditions.
What's different
Same physics. Different experience.
Motor Current Signature Analysis has existed for over 40 years. It works — but it requires a specialist, a scheduled visit, and manual interpretation. SAM4 turns ESA into a continuous, automated service.
Legacy MCSA
- Monitoring mode Periodic — scheduled visits
- Operator Specialist with oscilloscope
- Data interpretation Manual expert analysis
- Scale One asset at a time
- Output Report (days–weeks later)
- Fleet coverage Typically 5–20 critical assets
SAM4 ESA
- Monitoring mode Continuous — 24/7 automated
- Operator No specialist required
- Data interpretation AI models + diagnostic team
- Scale Entire fleet simultaneously
- Output Real-time alerts + dashboard
- Fleet coverage 1,000+ assets per site
The physics hasn't changed. The experience has — from a specialist tool to an operational platform your maintenance team can use.
See how ESA compares to vibration monitoring →Validation
From IEEE papers to 10,000 monitored assets
ISO 20958
The international standard for condition monitoring using electrical signatures. SAM4's approach aligns with ISO 20958 methodology.
ABB integration
ABB evaluated every ESA approach on the market and chose Samotics. SAM4 ESA is integrated into ABB's ACS880 drives. ABB holds a 10% equity stake.
Peer-reviewed research
ESA methods have been published in IEEE, EPRI, and leading journals since the 1980s. The physics is established.
“Instead of needing to be placed on the asset in the field, SAM4 installs inside the motor control cabinet, out of harm's way. And its advanced analytics were just what we needed.”
See SAM4 ESA with your own data
Request a demo and speak with one of our reliability engineers. We'll show you what ESA detects on assets like yours.