How low have mains frequencies gone? What areas once used 30 Hz, and why?

Votes are +10/-3, there are three good answers with summed votes +18/-0, and the answers.

The stated close reason is:

Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design.

I'm not sure how this applies because design of a power distribution includes the choice of mains frequency (in this case as low as 30 Hz) and this is certainly a circuit, and questions about mains power distribution are demonstrably on-topic (I can find many that are well-received and answered).

The only negative comment I've found is that it lacks

enough effort or EE aptitude

but I don't know if that's the reason this question was closed or not.

So my questions are only:

  1. Was this question likely closed for the stated close reason, or for a different reason that's not stated?
  2. What edits can be done to address either the stated or the likely close reason that wouldn't conflict with the existing answers?

One edit I can think of off the top of my head is moving the "why?" to the beginning of the title.

  • \$\begingroup\$ Possibly because the title had 3 different history questions with volumes written about the subject. Perhaps reasons like too many questions with 1st two could be answered by basic history research and the last needing a long debate about efficiency and costs. . In any case I think I was the only person who both criticized and answered the 1st question instantly. 16Hz for railways by Siemens in 1904. \$\endgroup\$ Jan 6, 2020 at 11:21
  • \$\begingroup\$ Thanks, I'm looking for the actual close reason. Also, that doesn't address the "why". \$\endgroup\$
    – uhoh
    Jan 6, 2020 at 12:02
  • \$\begingroup\$ I guess the historical use of 30 Hz is off-topic \$\endgroup\$ Jan 6, 2020 at 12:04
  • \$\begingroup\$ I won't take that seriously unless you post it as an answer and others can vote on it. Let's get some community consensus. \$\endgroup\$
    – uhoh
    Jan 6, 2020 at 12:05

1 Answer 1


This question was closed because 5 people were of the opinion that it didn't conform to the stated mission of this forum:

Electrical Engineering Stack Exchange is a question and answer site…. …we're working together to build a library of detailed answers to every question about electronics [and electrical engineering] design [and theory]…. This site is all about getting answers. It's not a discussion forum.

Focus on questions about an actual problem you have faced. Include details about what you have tried and exactly what you are trying to do.

Avoid questions that are primarily opinion-based, or that are likely to generate discussion rather than answers.

The stated reason is actually just a box that was checked by more voters than any other. The real reason can only be determined by interviewing the voters. That is often the case.

In my opinion, the question is largely opinion based. As a history question, it does not pertain to an actual problem that anyone is facing today. The answers are not very likely to be useful for the education or assistance in the field today. That is not to say that the question and answers lack value, but only that they do not serve the purpose of this forum. I hope answers answers and comments provided are of some value to the asker, but I don't think they contribute to the mission of this forum. For those reasons, I provided an answer but voted to close the question.

  • \$\begingroup\$ Thank you for taking the time to post a thoughtful answer! I did indeed receive plenty of helpful information and perspective in the several answers and many comments there, so it was a happy ending for me, and while closed the answers are still available to future readers. \$\endgroup\$
    – uhoh
    Mar 1, 2020 at 23:46
  • \$\begingroup\$ I hope to follow up on the whole topic of thickness of laminations versus frequency thing but I'll need to do my homework first (checking this site and reading elsewhere), and if I do ultimately find a new question to ask that's not already answered here I'll try to make sure that answers will "contribute to the mission of this forum." \$\endgroup\$
    – uhoh
    Mar 1, 2020 at 23:48

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