Recent technical evaluations at Wolong Electric Nanyang Motors have focused on a recurring issue observed in explosion-proof motors: shaft currents. These unwanted electrical currents, if left unmanaged, can lead to premature bearing failure, increased maintenance, and a heightened risk in hazardous environments. With explosion-proof motors being vital for industries like petrochemical, mining, and gas processing, addressing this issue is a critical step in ensuring long-term reliability and operational safety.
Shaft currents in explosion-proof motors typically originate due to a combination of electromagnetic asymmetries, high-frequency voltages from variable frequency drives (VFDs), and poor grounding techniques. The use of VFDs, while improving control and efficiency, introduces common-mode voltages that can induce circulating currents through the motor shaft and into the bearings. In explosion-proof motors, where robust design is necessary to contain sparks or arcs, these currents can compromise the insulation and lead to dangerous situations.
At Wolong Electric Nanyang Motors, engineers have identified several contributing factors to this issue. First, imbalanced magnetic fields caused by improper rotor-stator alignment often generate axial flux, which can induce current on the shaft. Second, insufficient bearing insulation or lack of shaft grounding brushes increases the vulnerability of the motor to circulating currents.
To counter these risks, Wolong has developed a three-tiered mitigation strategy. It begins with improving electromagnetic symmetry during the motor’s assembly process. Next, they’ve integrated insulated bearings or ceramic-coated bearing housings to break the current path. Finally, custom-designed shaft grounding rings are installed to safely redirect stray currents away from sensitive components.
Additionally, Wolong has enhanced its testing protocols by using shaft voltage detection instruments during factory testing. These tools identify residual shaft currents before the motor is deployed in explosive zones. This preemptive measure ensures that every explosion-proof motor meets global compliance standards like IECEx and ATEX before reaching the field.
Industry analysts note that solving shaft current issues not only extends motor lifespan but also plays a significant role in reducing unplanned shutdowns in critical operations. As companies worldwide seek safer and more energy-efficient machinery, the innovations led by Wolong Electric Nanyang Motors demonstrate their commitment to engineering excellence in the explosion-proof motor category.
The company continues to collaborate with major industrial automation partners to integrate condition monitoring systems. These IoT-powered tools allow real-time tracking of shaft voltage levels and predictive alerts, transforming traditional motors into smart, self-protecting assets.
