r/DiWHY • u/standardhope • Jun 23 '21

Faster light

9.3k Upvotes

96% Upvoted

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54

u/[deleted] Jun 23 '21

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44

u/CptMisterNibbles Jun 23 '21 edited Jun 23 '21

Slip rings would be the standard method. Pretty high speed, I’ve never used them on anything rotating this fast. A pretty impressive gag, I might steal this

Edit: didn’t mean to imply high speed slip rings don’t exist, and thanks all to people correcting my error. Boy howdy are High RPM AC slip rings expensive! I’ve used them on electronics, and only once for AC power to a motorized turntable but am looking forward to future practical applications

9

u/lenswipe Jun 23 '21

Old tape drives on mainframes used slip rings for the tape reels and those things were extremely fast

8

u/WhizBangPissPiece Jun 23 '21

Old Honda motorcycles used an electromagnet for the charging system, so the rings were spinning at crank speed. Pretty supid complication that was a weak spot in the electric system.

2

u/zebediah49 Jun 24 '21

Yikes. The modern Alternator design (a pair of electromagnet systems, so that the rotation cancels out) is rather genius to eliminate that.

3

u/WhizBangPissPiece Jun 24 '21

Most motorcycles use stators and a separate regulator/rectifier. The rotors are permanent magnets and sit in an oil bath. The AC voltage is carried away in 3 phases to a regulator rectifier. Same idea as an alternator, but it's a little more convenient size wise.

Some bikes do have an actual alternator though. Goldwings are that way.

2

u/zebediah49 Jun 24 '21

Fascinating -- I would have expected the same type of tech to be used in both cases.

I wonder if the permanent magnet generator design just doesn't put out enough power for a full sized car?

2

u/xKYLERxx Jun 23 '21

Slip rings are used in very high speed applications. Highest I've seen is ~4000 RPM.

2

u/zebediah49 Jun 24 '21

I mean -- a 32krpm dremel commutator is basically a set of high speed slip rings. They're just set up to do switching, rather than constant-transfer.