Nonstock CBO43HP1/4-50A4 Inductive Absorber Ring Vfd

Product Description

The NONSTOCK CBO43HP1/4-50A4 is an inductive absorber ring engineered to protect motor bearings from circulating currents generated by variable frequency drives (VFDs). It functions as a common-mode choke ring, attenuating harmful electrical frequencies that travel along the motor shaft and through the bearing races. Left unchecked, these VFD-induced currents cause electrochemical pitting and fluting on bearing surfaces, leading to premature failure. This ring installs directly on the motor shaft or housing to interrupt the current path before damage occurs. It is a passive, low-maintenance component suited for motors operating on VFD-controlled circuits in HVAC, pump, fan, and general industrial drive applications.

This inductive absorber ring is used in motor installations where a VFD is the drive source and bearing protection is required. Common applications include commercial and industrial HVAC fan motors, pump motors, and compressor drive motors connected to variable frequency drives. It is appropriate for both new installations and retrofit projects where bearing failure has been traced to VFD-induced common-mode currents. Electricians and motor service technicians typically install this component as part of a broader VFD mitigation strategy that may also include shaft grounding rings and shielded cable.

Key Features

• Functions as a common-mode choke ring to suppress VFD-induced circulating currents
• Helps prevent electrochemical bearing pitting and fluting caused by shaft currents
• Passive design requires no external power or ongoing maintenance
• Ring form factor allows straightforward installation on motor shaft or housing
• Applicable to retrofit and new-installation motor protection scenarios

Compatibility

Designed as a common-mode choke-style inductive absorber ring for motors operated by variable frequency drives where bearing current mitigation is required.

Installation Notes

Installation is typically performed by a licensed electrician or qualified motor service technician. De-energize and lock out the VFD and motor circuit completely before handling any motor components. Follow the motor and VFD manufacturer mounting instructions for ring placement to ensure proper common-mode current attenuation. Verify that all associated wiring and grounding practices comply with NEC requirements for VFD installations.