4 ms·
Wouldn't series wound DC motors have been an option? They're awful for a lot of reasons (low efficiency, brush wear, hard to do regen or even reverse without c
by elihu 3y ago
Wouldn't series wound DC motors have been an option? They're awful for a lot of reasons (low efficiency, brush wear, hard to do regen or even reverse without complex switching mechanisms, etc...) but they're simple and don't use permanent magnets and can be quite powerful.
I don't know when SWDC motors were invented but I would have assumed it was long before the 90's.
- cyberax 3y agoUhm, that's what I said. Before IGBTs, the main way you controlled a powerful DC motor was by having multiple windings that can be connected in parallel or series configurations, modulating the resulting current. This type of control goes way back to 19-th century, it was used on the first trams.
- mitthrowaway2 3y agoelihu is talking about using a universal motor to mitigate the rare-earths aspect: https://en.wikipedia.org/wiki/Universal_motor https://en.wikipedia.org/wiki/Universal_motor
- cyberax 3y agoSorry, I misunderstood that. I was still thinking about controlling the power, my bad.
- elihu 3y agoYou said: "Before that, you in practice had been limited to synchronous permanent-magnet DC motors." Series-wound DC motors don't have permanent magnets at all -- rather, they have two sets of windings (connected in series) that push against each other, so there would be no concerns about rare earths. I don't know what a "synchronous" DC motor is, unless you meant to say "synchronous AC and permanent magnet DC."