| ▲ | cesarb 2 days ago | |
> Any electricity produced by turning generators will require rare earths. AFAIK, not all kinds of rotating generators require rare earths; IIRC, induction motors don't need any permanent magnets. | ||
| ▲ | immibis 2 days ago | parent [-] | |
AFAIK, modern wind turbines use types of induction motors because it allows them to adjust the rotation speed by applying a counter-rotating stator field (which is a very neat trick) - older turbines had to rotate at a fixed divisor of 3600 rpm (grid frequency). | ||