Electric speed increasing attachments operate closer to a low speed gear angle than a high speed air turbine. There are two bearings in the head that can be replaced like a high speed turbine, but the power is transferred to the head by a series of gears. While quite durable, these individual gears will eventually wear or become damaged requiring replacement.
Stop Using Immediately IF
Basic rebuild where the bearings are failing but the gears are not damaged.
Head cartridge gear damage or not retaining the bur properly.
Extensive gear damage though out the attachment.