IEEE IAS-PCIC 2026 Technical Paper

Wolong Presents Test-Based Approach to Shaft Bonding Device Qualification

At the 2026 IEEE IAS Petroleum and Chemical Industry Committee (PCIC) Technical Conference, Wolong Electric America presented research on shaft bonding device qualification for VFD-fed motors in hazardous locations. The work examines how a test-based approach to discharge-energy calculations can support a more accurate evaluation of shaft bonding devices when shaft-voltage or VFD common-mode-voltage data is unavailable.

Saikh Sahid Parvez and Diana Barbosa of Wolong Electric America’s engineering group presented the technical paper, “Optimize Qualification of Shaft Bonding Devices in Hazardous Locations for VFD-Fed Horizontal Motors by Addressing IEEE 1349 Limitations with Optimized Discharge Energy Calculations.” The presentation examined a test-based approach to optimizing discharge-energy calculations for shaft bonding device qualification in Class I, Division 2 hazardous locations.

The IEEE IAS-PCIC Technical Conference brings together electrical professionals from the petroleum, chemical and broader process industries to discuss industrial electrical installations, operations and safety. Wolong’s presentation contributed to the technical conversation around VFD motor bearing protection, hazardous-location compliance and practical specification decisions.

Shaft Bonding Devices for VFD Motors

VFD-fed motors can be subject to electrical discharge conditions that may damage motor bearings. Shaft bonding devices can help protect bearings from this damage by providing a controlled path for shaft currents.

In hazardous locations, however, shaft bonding device qualification requires engineers to demonstrate that the resulting discharge energy is nonincendive for the specific application. That evaluation can be particularly challenging during early project design and specification, when motor shaft-voltage test data or VFD common-mode-voltage (CMV) information is not available.

Improving IEEE 1349 Discharge-Energy Calculations

IEEE 1349-2021 provides guidance for calculating discharge energy based on motor and drive characteristics. In practice, several of the inputs needed for this calculation may be difficult to obtain:

• Shaft-voltage test data may not be available during the motor design or specification stage.

• Testing every motor during manufacturing may not be practical.

• VFD common-mode-voltage data is not commonly published by drive manufacturers and can vary by drive type.

• Default assumptions may result in discharge-energy estimates that are more conservative than necessary.

Wolong’s research presented a systematic, test-based approach informed by extensive testing of low- and medium-voltage NEMA motors. The methodology is designed to reduce dependence on unavailable VFD manufacturer CMV data and support a more accurate assessment of discharge energy for shaft bonding devices.

For engineers and specification professionals, this approach can offer a more practical way to evaluate shaft bonding device suitability while maintaining the safety requirements needed for hazardous-location applications.

Evaluating Roller-Bearing Motors

Wolong’s research also addressed an application gap involving roller-bearing motors.

The calculation approach in IEEE 1349-2021 is limited to horizontal machines with ball or sleeve bearings. However, many industrial motor applications use roller bearings. Wolong introduced a methodology for calculating discharge energy in roller-bearing motors, helping engineers evaluate shaft bonding devices across a broader range of VFD-fed motor configurations.

This capability is especially relevant for petroleum, chemical and other process-industry facilities, where motor reliability, hazardous-location safety and specification compliance are essential.

Advancing VFD Motor Safety

Wolong Electric America values the opportunity to share this work with engineers, end users, specification professionals and industry peers at IEEE PCIC 2026.

As VFD-fed motor applications continue to expand across process industries, dependable approaches to motor bearing protection and shaft bonding device qualification remain important. Through ongoing testing and application-focused engineering, Wolong is helping customers make informed decisions for demanding industrial environments.