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ABB Air Gap Inspector


Robotic Inspection of Motors and Generators Improves Maintenance

ULC Technologies partnered with industry leader ABB to create the Air Gap Inspector, a groundbreaking magnetic robotic crawler designed to revolutionize the inspection of large motors and generators worldwide. Combining ABB’s engineering expertise with ULC’s robotic systems innovation, this project delivered a game-changing solution capable of entering air gaps as small as 10mm, providing precise video and location data for in-depth inspections. 

From proof of concept to production, our collaborative effort has resulted in a cutting-edge system that empowers asset owners with the insights they need to make informed maintenance decisions.

The ABB Air Gap Inspector Robot is now deployed commercially by ABB Ability™ LEAP across the globe.

Key Benefits

Modular Design

The robot crawler’s modular design is adaptable to various motor and generator configurations, accommodating different stator teeth widths and teeth-to-slot-width ratios.

Versatile & Detailed Inspection

The robotic crawler can inspect air gaps as small as 10 mm, a task typically only possible with rotor removal. It provides a detailed inspection of the stator and rotor cores, windings, and the inside part of the motor or generator.

Fault Localization & Rotor Preservation

It can pinpoint and record the position and severity of certain faults without rotor removal. By avoiding rotor removal for inspections, it helps extend the lifespan of critical components, reducing maintenance costs.

Efficient Minor Outages

Inspection can be performed during minor outages without the need for rotor removal, streamlining maintenance processes.

Adjustable Focus

Operators have the flexibility to adjust the orientation of the crawler and the camera focus as needed before inserting the ABB Air Gap Inspector into the air gap.

Enhanced Analysis

It complements ABB’s LEAP Standard program by combining visual inspection of the inside, improving the quality of analysis.

System Features

Equipped with 5 high-resolution onboard cameras with variable-intensity LED lighting, the 8.5-mm-tall crawler provides real-time video footage including forward, ventilation slot, rotor surface, various stator lamination, and rear views.

Adjustable modular magnetic tracks allow for operation across various stator designs, featuring automatic travel along the stator core, accommodating core lengths up to 5 meters.

When combined with a life expectancy analysis test, the Air Gap Inspector empower owners of motors and generators to make informed decisions – potentially saving customers millions of dollars by precisely determining the optimal timing for rotor replacement.

How it Works

The motorized crawler magnetically attaches to the stator surface and is driven in the air gap at different slot positions to capture full video and imagery of the air gap, offering invaluable qualitative insights that supplement electrical testing to help pinpoint issues including:

  • Broken laminations
  • Core burns
  • Blocked vent ducts
  • Effects of spark erosion and bulging
  • Signs of movement at slot exit or in vent ducts
ABB + ULC Technologies

Engineering Excellence. Driving Results.

ULC Technologies partners with industry leading companies to develop and commercialize solutions such as the ABB Air Gap Inspection Robot. Connect with our team to learn how we can innovate together.

Project Partners

ULC Technologies

ULC Technologies works with leading utility and energy companies to develop and deploy robotic systems, inspection systems, machine learning and technology that helps reduce public disruption, minimizes environmental impact and improves safety.


ABB is a technology leader in electrification and automation, enabling a more sustainable and resource-efficient future. The company’s solutions connect engineering know-how and software to optimize how things are manufactured, moved, powered and operated.

“Like a surgeon’s precision scalpel, the ABB Air Gap Inspector unveils the hidden intricacies of motors and generators, ensuring their heart – the air gap – beats with unparalleled vitality.

A. Shah, Project Manager, ULC Technologies

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