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Is 90% efficiency really feasible for electrical -> mechanical -> electrical?
by gatehouse 12y ago
Is 90% efficiency really feasible for electrical -> mechanical -> electrical?
- KaiserPro 12y ago95% efficient each way, it does sound a bit much.
- tormeh 12y agoNot really. Electrical engines and generators are incredibly efficient. It's not the transition there that is the problem. In fact, if it was only for that loss the efficiency would be more like 97%. The problem is the friction in the mechanical parts; the wires, gears and so on.
- andrewflnr 12y agoDang, that's impressive. I had no idea electrical<->mechanical conversion was so efficient.
- bodyfour 12y agoThink about how little cooling is needed on a big electric motor. Even motors made 100 years ago are very efficient. By contrast anything that qualifies as a "heat engine" (including internal combustion) is limited by Carnot's law to be low-efficiency. If it weren't for the extraordinary energy density of combustible fuels they wouldn't be competitive.
- tormeh 12y agoYes, the theoretical efficiency limit on electric engines and generators is 100%.
- tanzam75 12y agoAmtrak still uses motor-generators on some parts of the Northeast Corridor to convert 60 Hz AC grid power to 25 Hz AC traction power. It's exactly what it sounds like: a motor that is mechanically coupled to a generator. The motor runs on 60 Hz AC and turns the generator at the correct speed to produce 25 Hz AC.
- tormeh 12y agoHaha, wow, a mechanical engineer was on duty that day.
- troymc 12y agoToday, the majority of grid energy storage is done using pumped-storage hydroelectricity (PSH). "PSH reported energy efficiency varies in practice between 70% and 80%, with some claiming up to 87%." [1] [1] https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit...