| VFD Induced Shaft Currents
Damaging voltages are induced on the shafts of AC and DC motors controlled by variable frequency drives (VFD). The extremely high on/off switching speeds of the pulse width modulation (PWM), generated by the insulated gate bipolar transistors (IGBT), induce damaging voltages onto the motor shaft through parasitic capacitive coupling between the stator and rotor. This common mode shaft voltage seeks a path to ground, usually through the motors bearings.
BEARING PROTECTION FACTS:
Bearing protection for motors and attached equipment: Only AEGIS®SGR will protect both motor bearings and the bearings in attached equipment. VFD induced currents on the shaft can discharge through motor bearings or coupled equipment like gear boxes, pumps. fan bearings, pillow blocks, encoders, brake motors, etc. AEGIS®SGR addresses the root of the problem and channels harmful currents to ground.
AEGIS® SGR is effective in grease, oil, dirt or dust: Lab and field tested. The conductive micro fibers "sweep" away contaminants from the shaft surface and maintain a conductive path even when oil, grease, dirt or dust get on the shaft. The AEGIS®SGR Bearing Protection Ring is the only technology which works in contaminated environments.