Timeline for Advantage of using AC generators in cars instead of DC generators
Current License: CC BY-SA 3.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Mar 4, 2017 at 2:28 | comment | added | Harper - Reinstate Monica | For that matter, permanent magnets can be used to activate an exciter winding which can then feed power into the generator field. | |
| Mar 3, 2017 at 14:21 | comment | added | Martin James | @Trevor yes, the low duty-cycle means even more economies in construction. Since most engines, (with their computerized injectors, ignition etc), start first time these days, I suspect that starters are now even more lossy and likely to fail than in previous decades:( | |
| Mar 3, 2017 at 14:02 | comment | added | Trevor_G | That's true @MartinJames, but then most starter motors run for only seconds a day. Even then, they are replaced almost if not more often than alternators. | |
| Mar 3, 2017 at 12:59 | comment | added | Martin James | Well, commutators with low contact resistance can be built - one is used in the starter motor - a machine which must handle very high rotor current in order to produce enough torque to turn over a cold internal combustion engine against the opposition of thick oil, cold-reduced clearances and, with diesels, high compression. High commutator losses would leave you stranded:( | |
| Mar 3, 2017 at 11:17 | vote | accept | M.A.K | ||
| Mar 3, 2017 at 11:09 | comment | added | user16324 | Just to reinforce the efficiency point, alternators take something like 30-40W to generate the magnetic field ( according to Hugh Piggott's work on small wind turbines) so a permanent magnet AC generator (PMSM or BLDC motor) would be more efficient. But 30-40W loss is currently regarded as acceptable when driven from a 30-40kw (or more) engine. And permanent magnets cost money... | |
| Mar 3, 2017 at 10:56 | history | answered | Marcus Müller | CC BY-SA 3.0 |