There are quite a few old fashioned elevators that are still equipped with their original DC motors.

Note the construction of these motors resemble those in Edison's drawings and the illustrations in physics books.

 

If you ever make it to Pittsburgh (the Pittsburgh with an "h"), you'll see this marvel, running about 6x per hour. Built in 1877.

The motors look similar and the big gear is cast iron with wooden (maple) teeth.

The round trip ride is $5 but the self-guided tour below for $1 is the best part (bring quarters). You can park low or high to start your round trip.

https://en.m.wikipedia.org/wiki/Duquesne_Incline

If you don't like this one, there is a second one about 2-miles east.

 

One of the building I worked in had one of those motors on the freight elevator, it never had problems. The ones that had a newer style motor on the other hand...

 

Engineered and built to last. That's what 'Made in USA' is supposed to mean. Organizational behavior has changed, and profits are the ultimate goal of modern capitalism. Adam Smith is rolling in his grave. Where has pride of workmanship gone?

 

Engineered and built to last. That's what 'Made in USA' is supposed to mean. Organizational behavior has changed, and profits are the ultimate goal of modern capitalism. Adam Smith is rolling in his grave. Where has pride of workmanship gone?

Optimization. Whether it is business process optimization, manufacturing optimization, weight optimization, cost, ...

Those damn engineers always have to diddle with something....

 

Engineered and built to last. That's what 'Made in USA' is supposed to mean. Organizational behavior has changed, and profits are the ultimate goal of modern capitalism. Adam Smith is rolling in his grave. Where has pride of workmanship gone?

The problem now is everything is designed to fail because selling parts and service ing things is where companies make all the money.

The majority of people wont spend the money to have a high quality well built device now but they are all too happy to spend way more over a longer period of time in operating costs with a cheap inferior design in operational costs over its lifetime than what the one well built unit would have cost.

I see that all the time with farming equipment now. Everything is junk on the actual build quality and durability aspects. Around here it's common to find tractors and other machinery from the 1960's and older that are still running on all major engine and driveline components with 10,000 - 20,000 hours of long hard used lives.

The newest stuff rarely hits 2000 - 3000 hours run time now without major breakdowns in those mechanisms.

One of our old tractors is a 1950's IH 560D diesel and back in its day it was well known for having a 'weak engine design' because it was only good for 6000 - 8000 running hours before needing major rebuild which kits for them today only run about $1500 -1800 for full overhaul.

Now the modern good tractor is good for 1/3 - 1/2 that and costs over 10x that on a similar rebuild. We have two 1980's tractors that both have just short of 3000 hours on them and both came with new low hour engines in them when we bought them and thats considered normal life expectancy now.

 

The problem now is everything is designed to fail because selling parts and service ing things is where companies make all the money.

The majority of people wont spend the money to have a high quality well built device now but they are all too happy to spend way more over a longer period of time in operating costs with a cheap inferior design in operational costs over its lifetime than what the one well built unit would have cost.

I see that all the time with farming equipment now. Everything is junk on the actual build quality and durability aspects. Around here it's common to find tractors and other machinery from the 1960's and older that are still running on all major engine and driveline components with 10,000 - 20,000 hours of long hard used lives.

The newest stuff rarely hits 2000 - 3000 hours run time now without major breakdowns in those mechanisms.

One of our old tractors is a 1950's IH 560D diesel and back in its day it was well known for having a 'weak engine design' because it was only good for 6000 - 8000 running hours before needing major rebuild which kits for them today only run about $1500 -1800 for full overhaul.

Now the modern good tractor is good for 1/3 - 1/2 that and costs over 10x that on a similar rebuild. We have two 1980's tractors that both have just short of 3000 hours on them and both came with new low hour engines in them when we bought them and thats considered normal life expectancy now.

Bad USB yokes and sockets

 

I have no experience with the DC motors, but AC motors of the boat-anchor class are the very best for converting single phase to three phase. The do weight a lot.

John

 

I remember reading in the "They Are Still Here" column of American Heritage of Invention and Technology magazine about a machine shop that still used motors that ran at something like 25 Hz. The power company was required to supply power to them as long as they stayed in use.

 

I remember reading in the "They Are Still Here" column of American Heritage of Invention and Technology magazine about a machine shop that still used motors that ran at something like 25 Hz. The power company was required to supply power to them as long as they stayed in use.

SEPTA still operating on 25 Hz
https://en.wikipedia.org/wiki/SEPTA's_25_Hz_traction_power_system

Amtrak still operating on 25 Hz
https://en.wikipedia.org/wiki/Amtrak's_25_Hz_traction_power_system

Safe Harbor Dam - still generating 25 Hz for two railroads...
https://en.wikipedia.org/wiki/Safe_Harbor_Dam

 

SEPTA still operating on 25 Hz
https://en.wikipedia.org/wiki/SEPTA's_25_Hz_traction_power_system

Amtrak still operating on 25 Hz
https://en.wikipedia.org/wiki/Amtrak's_25_Hz_traction_power_system

Safe Harbor Dam - still generating 25 Hz for two railroads...
https://en.wikipedia.org/wiki/Safe_Harbor_Dam

Interesting links.

If I remember right the machine shop was in New York City. The power company probably was running a motor generator set just for the machine shop.

 

I remember reading in the "They Are Still Here" column of American Heritage of Invention and Technology magazine about a machine shop that still used motors that ran at something like 25 Hz. The power company was required to supply power to them as long as they stayed in use.

What were the advantages of switching to 60 Hz then?

 

What were the advantages of switching to 60 Hz then?

Electrical transmission, induction motor design, voltage conversion (transformer etc).
Max.

 

What were the advantages of switching to 60 Hz then?

A transformer at 30Hz is about 2x bigger than a 60Hz transformer.

Even incandescent lights have a visible flicker at 30Hz - especially when in your peripheral vision.

The caps in any DC power supply have to be much bigger for the same load regulation of the same load.

 

The caps in any DC power supply have to be much bigger for the same load regulation of the same load.

Which begs the question, why not a higher frequency than 60 Hz then?

I'm guessing that the answer lies in the number of windings needed in a generator... which would in turn make it more expensive to fabricate

 

Which begs the question, why not a higher frequency than 60 Hz then?

The aircraft industry uses 400Hz to save on weight and size, however the down side is it is less efficient than the 60Hz version.
Max.

 

The aircraft industry uses 400Hz to save on weight and size, however the down side is it is less efficient than the 60Hz version.
Max.

So the 30Hz version of a motor would be even more efficient?

My question is directed at: what would be the perfect frequency for today's industry, if standards were to be redefined?

 

As mentioned, lower freq causes lamp flicker, especially now in the advent of florescent light.
I think I mentioned this before, when I worked in the electrical industry in the UK, I remember the introduction of fluorescent light in the workplace etc.
It was found early fixtures exhibited a barely detectable 50Hz flicker, when banks of florescent fixtures were installed in machine shops, the stroboscopic effect on milling machine tool tooling gave the impression of a stationary spindle.
The result was some lost fingers due to this, the correction for this was the banks were then wired across 3 phases, reducing or eliminating the effect.
Max.

 

Here is a link to the archived magazine I mentioned above. (I did not look for the article I mentioned.)
Danger!!! This can (will) be a real time sink.

https://web.archive.org/web/20110320213622/http://www.americanheritage.com/articles/magazine/it/


@cmartinez It won't answer your questions but there was also an article in the same magazine about California modifying electric clocks to the new line frequency when 60 Hz became standard.

 

Here's a link to the history of Llewellyn Iron Works which was one of the largest elevator manufacturers in Los Angeles between the 1920s and late 40s:

https://archive.org/details/Elevators_46

Llewellyn operated an iron and bronze foundry that built the mechanical components of the elevator and Westinghouse provided the motors. However, the company evolved from pure mechanical fabrication into a complete elevator builder including control system engineering and it also designed variable speed DC drives using generator field control.

I believe Westinghouse bought Llewellyn's elevator division and that's how Westinghouse got in the national elevator business.