This paper investigates the effect of voltage stress on the voltage insulation components inside a regenerative active-front-end adjustable-speed drive (ASD). It shows that a high potential voltage insulation issue may exist on various components inside the ASD and cause earlier failures. A simplified system model to describe this phenomenon is described, and the voltage stresses of different components inside the ASD under different grounded conditions and filter capacitor are analyzed. It is concluded that among different grounding systems, a high-resistance grounded system gives minimum stress. Appropriately, designing the insulation components is critical to protect the drive
