Indeed this is true for modern versions, but DC Muffin fans from the 1960s
had brushes (electronic comutation would have been large and of
prohibitive
expense).



They had DC muffin fans in the 60s? I don't recall ever seeing one, what
were they used in? I've seen AC muffin fans powered by shaded pole motors,
and a few DC fans that were just a fan blade stuck on the end of a little DC
motor, but I've never come across one I'd call a muffin fan.