Rotor condition
Assess current-signature features that may be consistent with rotor-bar or end-ring change.
Online motor current signature analysis
Read the motor and driven load through the current they draw.
ConditionCore uses Motor Current Analysis (MCA) as its product-facing label for online motor current signature analysis, commonly abbreviated MCSA. The workflow is designed to accept three-channel motor-feeder line-current waveforms and spectra, preserve the motor, feeder, supply, drive, speed, slip and load context, then compare qualified signatures with the rest of the machine evidence.
Motor Current Analysis (MCA)
An electrical signature needs motor and supply context.
For an energized three-phase induction motor, keep the feeder, acquisition method, supply type, speed, slip, load and baseline attached before comparing signatures.
- Evidence
- Three-channel motor-feeder line-current waveform and signature
- Qualify
- CT setup, sample rate, supply, speed, slip, load and baseline
- Can support
- Electrical or electromechanical condition hypothesis at motor-system scope
Illustrative online signature workflow
Illustrative · not a customer resultKeep every current signature tied to its operating state.
Online current data becomes defensible evidence only when acquisition method, supply type, motor configuration, speed, load and a comparable baseline travel with it.
MTR-2 · three-phase induction motor Line-fed · 50 Hz · 4-pole · 1,482 rpm 72% load · stable interval · three CT channels
Qualified observation
A configured sideband family changed against a matched baseline.
This supports a targeted review, not a broken-rotor-bar declaration. Check phase voltage when available, load stability, speed or slip, motor design, vibration response and the driven machine before assigning cause.
Scope: online electrical signature analysis for energized three-phase induction motors, consistent with ISO 20958. This is not offline motor-circuit analysis. Line supply, VFD control and switching, voltage quality, driven-load modulation and acquisition settings can all shape the signature. Motor-feeder data collection must follow the site electrical-safety programme and be performed by qualified personnel. Installed acquisition hardware or de-energized installation is preferred where feasible.
Data in
The context required for comparison.
Motor current is a machine-system response. Supply distortion, drive switching, motor design, speed, slip and driven-load variation can move or create spectral features. A current signature supports a hypothesis; it does not pinpoint GBX-2 or confirm a rotor, bearing or insulation fault by itself. This workflow follows the ISO 20958 scope for energized three-phase induction motors. Other motor and drive types require method-specific acquisition and interpretation.
- Three-channel motor-feeder line current
- Current spectrum and demodulated spectrum
- Line voltage, when available
- Measured speed, slip and load
- Motor nameplate, poles and connection
- Feeder, current-transformer, sample and VFD metadata
What it can reveal
What the measurement can support.
Air-gap eccentricity
Test expected signature families against motor design, speed, slip and load.
Supply and channel condition
Retain channel and available voltage context before interpreting imbalance or distortion.
Drive influence
Qualify possible VFD switching and control influence before assigning machine cause.
Load modulation
Relate torque and driven-load modulation to the connected motor, gearbox, pump or fan.
Cross-domain checks
Compare electrical signatures with vibration, thermal, ultrasonic and oil evidence without treating them as equal votes.
How ConditionCore uses it
From source data to a qualified observation.
Rotor, air-gap, supply and driven-load patterns in motor current, qualified by drive, speed, slip and load.
Acquire
Retain raw line current, available voltage, channel mapping, feeder point, current-transformer setup and sample settings.
Qualify
Retain line or VFD operation, motor data, sampling setup, speed, slip and load.
Compare
Assess repeatable signature change against a matched electrical and operating reference.
Correlate
Test rotor, air-gap, supply or driven-load hypotheses against the rest of the machine evidence.
Common questions
Motor Current Analysis (MCA), in practice.
See the controls required for a trustworthy comparison.
What does Motor Current Analysis mean on this site?
ConditionCore uses Motor Current Analysis (MCA) as its product-facing label for online motor current signature analysis, commonly abbreviated MCSA. ISO 20958 uses the broader term electrical signature analysis. This is distinct from de-energized Motor Circuit Analysis, which is also shortened to MCA.
What can motor-current signatures help reveal?
Qualified signatures can support hypotheses involving rotor bars or end rings, air-gap eccentricity, supply or phase condition, drive effects, motor loading and mechanical torque modulation reflected through the driven train.
Can Motor Current Analysis identify a gearbox fault by itself?
No. A driven-load change can modulate motor current, but current data usually cannot localize the physical source in the gearbox. Matched vibration, thermal, ultrasonic, oil and operating evidence are needed to test the mechanical explanation.
Can motor current analysis be used with VFD-fed motors?
Potentially, but the drive output frequency, control state, switching environment and matched reference must be retained. A threshold developed for a line-fed motor must not be transferred without validation.
Does motor current analysis replace vibration analysis?
No. Motor current adds an electrical and drive-train view. Vibration usually provides stronger mechanical localization. Their value increases when each is allowed to test the other without being treated as an equal vote.
First machine review
Start with the machine that is changing.
Share one changing asset and the files you already have. We will confirm what is usable, what remains uncertain and which next check is most valuable.
Request a machine review