US12573921USUSPTO Grant XML

Electro-magnetic shield to prevent bearing and/or gearbox damage due to shaft induced voltage in electric motors

Common mode voltage discharge shields are disposed over end turns of stator windings for a three phase electric traction motor within an electric vehicle. The common mode voltage discharge shields are capacitively coupled to the end turns to a ground strap, providing a low impedance path for common mode voltages accumulating at a neutral for electric traction motor as a result of high frequency switching of the motor drive voltage to produce desired torque. An insulating layer separates the common mode voltage discharge shields from the end turns. Accumulation of the common mode voltage in excess of a bearing breakdown voltage, and the associated potential for discharge through bearings between the stator and rotor and electrical discharge machining, is reduced or eliminated.

Patent

Brief

Patent brief

Problem

How can vibration in electric motors and rotors be reduced?

Novelty

The common mode voltage discharge shields are capacitively coupled to the end turns to a ground strap, providing a low i...

Uses

Patent review

Assignee

CANOO TECHNOLOGIES INC.

Published

Mar 10, 2026

Inventors

Amir Ranjbar

Domain

Electromechanical systems

Plain-English summary

Problem

How can vibration in electric motors and rotors be reduced?

Solution

Common mode voltage discharge shields are disposed over end turns of stator windings for a three phase electric traction motor within an electric vehicle.

Key novelty

The common mode voltage discharge shields are capacitively coupled to the end turns to a ground strap, providing a low impedance path for common mode voltages accumulating at a neutral for electric traction motor as a result of high frequency switching of the motor drive voltage to produce desired torque.

Applications

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