[tormeh]

Not 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.

[tanzam75]

Amtrak 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]

Haha, wow, a mechanical engineer was on duty that day.

[andrewflnr]

Dang, that's impressive. I had no idea electrical<->mechanical conversion was so efficient.

[bodyfour]

Think 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]

Yes, the theoretical efficiency limit on electric engines and generators is 100%.