Bearing Protection for Large Motors and Generators from Shaft Currents
AEGIS iPRO™ Shaft Grounding Ring
High frequency shaft voltages and currents, sometimes over 600 volts and 60 amps, cause motor and generator failures. This results in great costs due to plant and system failure, maintenance and downtime. The use of variable frequency drives (VFD/VSD) on large AC motors can induce high voltages on the motor shaft. Similar discharges may result from voltages arising from excessive static or the effects of electromagnetic induction caused by magnetic field asymmetry or residual magnetism. Unless protection is in place, once the voltage exceeds the breakdown strength of the bearing lubricant, these voltages discharge to ground, causing fusion craters in the bearings leading to motor failure. Other components such as gearboxes, shaft encoders, seals, etc. may also suffer damage.
iPRO Conductive MicroFiber™
The new AEGIS iPRO™ Conductive MicroFiber™ Shaft Grounding Ring reduces maintenance and prevents catastrophic failure by safely channelling harmful shaft currents to ground. Using proprietary Electron Transport Technology, the conductive microfibers inside the AEGIS iPRO™ provide the path of least resistance for damaging bearing currents, preventing electrical damage to motor bearings and dramatically extending motor and generator life.
High Shaft Current Bearing Protection
The AEGIS iPRO™ Shaft Grounding Ring has a high current carrying capability – up to 120 amps and can withstand 3000 volts peak. It allows a high current flow with no shaft arcing damage. The AEGIS iPRO™ shaft grounding ring is compatible with most shaft voltage and current monitoring systems. It is a reliable maintenance-free system with a lifetime generally similar to that of the motor.
The AEGIS iPRO™ Shaft Grounding Ring is ideally suited for large motors and generators above 1000kW because of its voltage and current characteristics. These rings are particularly invaluable in shaft grounding applications where the maintenance crew cannot access the plant between shutdowns.