I want to know the answer to the following question:
What problem arises for fast and large capacity elevators?
All the background I'm provided with is that "Historically, AC motors were used for single or double speed elevator machines on the grounds of cost and lower usage applications where car speed and passenger comfort were less of an issue, but for higher speed, larger capacity elevators, the need for infinitely variable speed control over the traction machine becomes an issue.". Is that enough to answer the question?
Answer: yes