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Comment on [discussion] DC (direct current) power network

empireOfLove2@lemmy.dbzer0.com ⁨3⁩ ⁨weeks⁩ ago

Well, most all DC generators these days are actually AC alternators with the output rectified, because alternators can be run a lot more efficiently. So you’re already losing on efficiency there.

You need to consider the consumer side as well. Dinky residential loads like your computer would be fine on DC. But most of the world, especially heavy industry, runs on synchronous or induction AC motors, big ones. Big huge tens-of-megawatts motors that often run upwards of 97% line efficiency, which is insane for any industrial process.
The best you could replace those with would be modern brushless DC motors, which require really expensive inverter controls that die frequently due to the magnetic transients and still top out at an efficiency of only 90% if you’re lucky. And that would incur huge costs that just aren’t worth it.

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BearOfaTime@lemm.ee ⁨3⁩ ⁨weeks⁩ ago

The best you could replace those with would be modern brushless DC motors, which require really expensive inverter controls that die frequently due to the magnetic transients

Wow, is this why my new brushless cordless tools have had more issues than my 25 year old cordless tools?

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- empireOfLove2@lemmy.dbzer0.com ⁨3⁩ ⁨weeks⁩ ago
  I mean, yes and no. A lot of that is modern tools are going to be more carefully engineered to operate as close to failure as possible, as to advertise more power with a cheaper device. Thry have small wires and encoder sensors that can be prone to failure.
  Yes, the driving electronics are also sensitive, but the brushless motors also do not have brushes that wear down rapidly in a very dirty/dusty contaminated environment like older power tools would. So it’s a bit of a 50/50.
  
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  - BearOfaTime@lemm.ee ⁨3⁩ ⁨weeks⁩ ago
    
    spikes that make solid state components Very Very Mad
    
    Hahaha, now I’m picturing an IC with an angry face just before it farts out Magic Smoke.
    
    Yea, I’ve had a couple new impact drivers needing the controller replaced, I assume they’re a package.
    
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    empireOfLove2@lemmy.dbzer0.com ⁨3⁩ ⁨weeks⁩ ago
    
    Hahaha, now I’m picturing an IC with an angry face just before it farts out Magic Smoke.
    
    Well, that’s basically how they behave too lol. Solid state power components are generally not very tolerant and require careful surge suppression and filtering to not have them blow up frequently.
    
    I bet if you took that 25 year old driver apart, sanded off the commutator rotor, and put new brushes in it you’d suddenly find it’d have more power and use less battery. (And thats something you can do with older tools!)
    When brushed motors get old and oxidation/dirt builds up the resistance across the brushes to the rotor coils grows and you’ll lose motor efficiency.
    
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