Also, it's not unheard of for low-end drive mfrs to just list a 480V drive as a 575V drive, basically taking their chances on the field return rate. There is one drive supplier that I KNOW for sure does this, because of you take their drives apart, you see that the power components for their 480V and 575V rated drives are 100% identical, meaning they are labeled for use at 480V.
And that then boils down to this:
When the semiconductor mfrs make the low voltage power devices, they don't really make 3 different versions: 240V, 480V and 690V*. They are ALL made to 690V design specs, and they TESTED to their individual limits prior to shipping. The highest volume of shipping are going to be 240V devices. So components to fill those orders are only tested to 240V and labeled for that. 99% of them pass and they get a greater return of that manufacturing investment, so the component price is the lowest. Then next is 480V and when they test them for 480V, something like 20% of them will fail. So to sell 1,000 components, they trash 250 of them and get zero return, so the sell price of the components labeled as 480V is higher to absorb those losses. Then at 500V, 600V, or 690V the failure rate climbs to >50%, so to sell 1,000 components, they trash over 1,000 of them and the amortized sell price for components labeled for those higher voltages reflects that.
When this company mentioned above sells their 575V drives, THEY are accepting that risk in their finished product, rather than the component mfr accepting it prior to shipping the parts. Unfortunately, the real cost ends up being born by the buyer, because even if the mfr replaces the drive under warranty, the down time it causes can cost a lot more than the part.
*We don't use 690V much in N. America, but it is used in other places in the world.
