Asset monitoring / Electric motors & VFDs

The motor is the sensor.
Start with its own health.

Rotor bars, stator windings, insulation, supply quality and VFD-induced bearing currents all change how a motor draws current. Artesis reads them at the MCC — for LV and MV motors, on DOL, soft-starter or VFD.

Discuss your motors ↗See the VFD case ↓

11 kVHighest motor voltage in the cases below

4 field casesPharma, power, glass and process

0 sensors on the motorCurrent and voltage measured in the MCC

01 / The challenge

Every asset has a motor.
Few are watched.

Motors drive pumps, fans, compressors and conveyors in every plant. Electrical faults — insulation breakdown, broken rotor bars, loose windings — can take a motor from normal to burnt in days.

VFDs add another risk: common-mode voltage can drive currents through the bearings and etch them. ESA reads both the motor’s electrical health and its mechanical condition from the same three phases.

Connect at the motor control cabinet

e-MCM uses the existing current and voltage signals, via CT/PT secondaries on MV motors.

Learn the motor’s signature

A model of each motor–load set is built under real operating conditions, including VFD speeds.

Separate motor from load

Findings distinguish stator, rotor, supply and bearing issues from driven-equipment problems.

02 / Featured case · Pharmaceutical

Bearings etched by the drive.
Shaft grounding confirmed as the fix.

DOCUMENTED FIELD CASE

CHILLER MOTOR / VOLTAGE AND CURRENT WAVEFORMS

Artesis AMTPro voltage and current waveforms with high-frequency distortion and crest factor values per phase

Distorted waveforms and elevated crest factors from the VFD.

CHILLER MOTOR / BEFORE AND AFTER SHAFT GROUNDING

Two Artesis AMTPro condition charts of the same chiller motor: with shaft grounding disconnected the stator indicator is in caution, with shaft grounding in place it is normal

A: grounding disconnected, stator indicator in caution. B: grounding in place, back to normal. Select to open full size.

A → B

Same motor, same day, one change
With the shaft grounding reconnected, the stator-related indicator dropped from caution back to normal.

Premature bearing failures, explained.

480 VNominal voltage

VFDDrive

ChillerDriven equipment

The problemA pharmaceutical site kept losing drive-end bearings on a VFD-driven chiller motor. The DE bearing had no insulation.

The findingAMTPro showed distorted waveforms and high crest factors — the conditions that drive bearing currents and electrical arcing. Maintenance found the fluting pattern on the failed bearing.

The confirmationTests on the same day with the shaft grounding disconnected and connected showed the stator-related indicator return to normal once the insulated bearing and grounding were in place.

1Repeated DE bearing failures
2Distorted waveforms, bearing currents
3Insulated bearing + shaft grounding

Source: Artesis Case Study 2024, slides 9–14, and AMTPro reports (June 2023). Customer name withheld.

03 / More field cases

Rotor bars
and stator windings.

3 INDUSTRIES

Artesis power spectral density of two identical 11 kV condensate pump motors, one with a rotor-related pattern

Power generation · Rotor bars

Cracked rotor bars on an 11 kV motor

A rotor-related pattern appeared on one of two identical condensate pump motors. An offline rotor test, repeated three times, confirmed cracked or defective rotor bars.

Rating: 11 kV · 32 A · 510 kW
More: Pump page →

Artesis MCM trend of the internal electrical fault parameter on a turbo compressor motor rising after restart

Glass · Stator windings

Loose windings rubbing the rotor

After five weeks out of service, a turbo compressor motor restarted and its internal electrical fault trend jumped. Three days later it was stopped: the stator windings had loosened and were rubbing the rotor.

Duty: Turbo compressor
Outcome: Stopped before a major failure

Process plant · VFD mixer

Fluting found where vibration missed it

An AMTPro test on a VFD-driven mixer indicated an outer-race bearing fault. Inspection found electrical fluting on the race — damage a vibration route had not caught.

Cases are individual outcomes from Artesis field deployments between 2005 and 2023. All visuals are from Artesis software. Customer names are withheld.

04 / What we detect

Fault modes, signals
and evidence strength.

Evidence strength reflects how reliably a condition produces an observable electrical pattern in typical motor installations — not a guarantee of detection.

Condition	What changes in the signal	Evidence	Field case
Motor · electrical
Broken or cracked rotor bars	Rotor-related pattern in the current spectrum	Strong	11 kV pump motor
Stator windings, turn-to-turn	Internal electrical fault indicator and phase balance	Strong	Turbo compressor
Insulation breakdown	Internal electrical fault trend, phase imbalance	Strong	—
Supply quality and connections	Voltage imbalance, THD, harmonics, per-phase RMS	Strong	—
Motor · VFD effects
Bearing currents and fluting	Waveform distortion, crest factor and bearing-related indicators	Good	Chiller motor →
Shaft grounding effectiveness	Indicator change with grounding in/out	Good	Chiller motor
VFD switching (IGBT) problems	Drive switching-related pattern in the high-resolution spectrum	Good	—
Motor · mechanical and load
Motor bearings	Bearing-related pattern in the current spectrum	Good	VFD mixer
Eccentricity and soft foot	Mechanical pattern in the current spectrum	Good	—
Oversized or underloaded motors	Load below ~60% of rating; energy effect	Strong	See fan pages

05 / Outside the envelope

Where electrical signatures are weaker.

We state the limits up front, so monitoring is set up where it adds most and paired with the right complementary checks.

Motors off most of the time

Standby motors need running time for data; use AMTPro when they run.

Very low VFD speed

Below about 20 Hz, diagnostic confidence is reduced.

Insulation to ground at rest

Offline insulation tests (IR, PI, surge) remain the tools for de-energised checks.

DC and special motors

Methods target AC induction motors; others need review case by case.

Observed patterns are interpreted by qualified personnel; they guide investigation rather than replace it. AMTPro spot tests need near-constant speed (±1% frequency) during capture.

06 / How you deploy it

Continuous where it matters.
Portable everywhere else.

Online · permanently installed

e-MCM

Critical LV and MV motors
24/7 learning, trending and alarms
Supports VFD applications
Results in OmniSight across sites

Portable · route-based

AMTPro

Fleet screening across hundreds of motors
Spot tests from the MCC in minutes
Automatic condition report per test
Energy impact estimate in every report

Artesis Insight explains the finding.

Artesis Insight turns spectra and trends into plain-language explanations and next steps. Your team does not need to be an ESA specialist to act on a result.

Illustrative maintenance guidance

Check for VFD bearing currents.

Distorted waveforms with high crest factor and bearing-related indicators suggest bearing currents. Check shaft grounding, insulated bearings and drive output filtering.

After action
Re-test with mitigation in place and confirm the indicators return to normal.

Example wording only; not a live alarm or a reproduced AI report.

07 / Applications

Any AC induction motor, any driven load.

LV induction motors from 1 kWMV motors via CT/PT secondariesVFD-driven motorsSoft-starter and DOL motorsStandby and spare motorsMotors in hazardous areas

Which motors can be monitored?

AC induction motors, low and medium voltage, on DOL, star-delta, soft-starter or VFD. MV motors are measured via existing CT and PT secondaries.

Can you detect VFD-induced bearing damage?

Yes. Distorted waveforms, high crest factors and bearing components point to bearing currents, as the featured chiller case shows.

Does it replace offline motor testing?

No. It complements it: ESA watches the running motor continuously; offline tests check insulation and windings when the motor is stopped.

Can hazardous-area motors be monitored?

Yes. The measurement is taken in the MCC, outside the hazardous area.

What information is needed to start?

Motor nameplate data, starter or drive type, driven equipment and the measurement points in the cabinet.

Related assets

Other equipment we monitor.

Bring your motors into view.

Tell us about your motor fleet. We’ll help you split it between online monitoring and portable routes.

Talk to Artesis ↗

Iron & Steel

Where continuous operation is crucial for maximum productivity, any failure in the smelting process can lead to substantial production delays and significant material costs. Artesis emerges as the ideal ally for the iron and steel industry, offering unparalleled condition monitoring tailored for challenging environments.

Energy

Artesis is here to support the energy sector with our advanced system for monitoring and predicting issues. In an industry where a steady power supply is crucial, our technology plays a key role in ensuring things run smoothly. Our special software is great at spotting potential problems early in rotating equipment, acting like an important early warning system. This is especially important in the energy sector, where unexpected breakdowns can lead to disruptive power outages affecting businesses, homes, and critical infrastructure. Artesis significantly contributes to the reliability of the energy sector by offering an effective predictive maintenance solution. By looking at patterns over time, our technology gives an early sign of possible issues. This helps grid operators plan ahead, taking actions to prevent power disruptions and ensuring a constant energy supply to industries and communities.

Logistic & Transportation

The logistic and transportation industry faces significant challenges when it comes to downtime costs, with unplanned disruptions leading to schedule delays, missed delivery dates, and additional charges. Artesis plays a crucial role in minimizing these challenges by providing continuous monitoring of asset health, offering timely insights into the need for repairs.

Automotive

Artesis introduces an advanced Predictive Maintenance (PdM) solution tailored for the automotive industry. Our system, Artesis e-MCM, is designed for simplicity, requiring minimal installation efforts and offering low start-up costs. With no need for sensor installation on equipment and the ability to function in non-EX areas, Artesis e-MCM is an ideal solution for inaccessible automotive equipment.

Food & Beverage

The food and beverage industry faces unique challenges, particularly concerning hygienic standards and safety. Artesis condition monitoring products emerge as a solution, offering a distinctive advantage—no sensor installation on the equipment itself. This not only ensures uncompromised hygiene but also addresses safety concerns seamlessly.

Pharmaceutical

Artesis’s condition monitoring and predictive maintenance solutions offer a comprehensive approach, encompassing failure prediction, fault diagnosis, failure-type classification, and recommendations for relevant maintenance actions. This empowers pharmaceutical equipment manufacturers, engineers, and process plant owners and operators to proactively identify and address potential issues, enhancing the efficiency of their maintenance services and improving equipment uptime.

Water

Artesis empowers water companies with continuous monitoring of aerators, centrifugal pumps, positive displacement pumps, mixers, clarifiers, and submerged equipment, preventing potential failures and optimizing asset performance and energy consumption. In the water industry, system downtime is both disruptive and costly. Artesis’s predictive maintenance and power monitoring solutions enhance operational efficiencies, prevent unplanned downtime, and extend the economic life of critical assets.

Oil & Gas

Knowing how rotating equipment is performing, predicting failures, improving asset utilization, and finding productivity enhancements in challenging environments are particular challenge for Oil & Gas companies. Artesis helps oil and gas companies predict their rotating equipment failures and prevents the unplanned downtime where the cost of downtime is extremely high. When oil and gas operations break down, it can have a significant domino effect on energy supply – making predictive maintenance technology a key ally for companies in the sector.

The motor is the sensor.
Start with its own health.