2012 Fisker Karma #1030
I couldn't find the answer to a question that came up today from someone who oggled my Karma. Are our electric motors DC or AC like Teslas?
AFAIK, absent abuse or extreme heat, the magnets used in electric motors retain their power, well, permanently. I don't think this is an issue you need to be concerned about.Thank you - so I assume that would mean over time the permanent magnets could weaken, whereas the Tesla battery would not. I wonder what the life of our magnets are?
Hope this helps.The magnets in permanent-magnet motors
Rare-earth elements are those 30 metals found in the periodic table’s oft-omitted long center two rows; they’re used in many modern applications. Magnets made of rare-earth metals are particularly powerful alloys with crystalline structures that have high magnetic anistropy — which means that they readily align in one direction, and resist it in others.
Discovered in the 1940s and identified in 1966, rare-earth magnets are one-third to two times more powerful than traditional ferrite magnets — generating fields up to 1.4 Teslas in some cases.
Permanent magnets are used in MRI machines, portable electronic devices, hysteresis clutches, accelerometers, and — last but not least —permanent-magnet rotary and linear motors.
OK; so it's an AC motor but it needs a bit of DC fluffing to get going, and honestly, who doesn't?Something that may be worthwhile mentioning is that the Fisker Karma motors are synchronous and thus require DC excitation so they are not really a pure AC motor in that they require a DC source to initialize rotation. These aren't pure AC PM motors from that perspective.