Well then, see it works.

On an unrelated side note Edison started with DC at the first NYC power station. While it took awhile to spread to Brooklyn, NY my grandfather had a house in the Park Slope section. Their early residential power was DC. Grandfather was a doctor so they had the devices of the day. Atwater Kent radio and of course an early refrigerator. When Consolidated Edison switched to AC they gave customers a huge rectifier box to convert the AC to DC for refrigerators. I discovered it in the basement of the old brownstone when I was a kid.

While I saw Edison as a great inventor and bright I also despise him for his business tactics including his electrocution of Topsy the elephant to promote his DC over AC. He was just a low life crooked bum. Albeit a wealthy pile of crap but nonetheless trash.

Ron

DC was still being distributed (might be still, but I don't know) in the 80s when we lived in Boston. It was used for elevators. There was a quite power electrical vault explosion involving DC that blew the manhole cover about 50 feet away. The vault was in the middle of the street, fortunately no one was hurt.

A firefighter pin the scene told me the DC caused them all sorts of problems because with high voltage, high current DC shorts cause a lot more explosive faults than AC. The DC infrastructure was very old, though. And it is not a good last mile distribution method.

 

I remember when in training working at the Oxford Observatory, converting the building from 110dc to 230vac.
The post with Ron was just the long distance DC transmission, converted back to 60hz AC this end.

 

DC was still being distributed (might be still, but I don't know) in the 80s when we lived in Boston. It was used for elevators. There was a quite power electrical vault explosion involving DC that blew the manhole cover about 50 feet away. The vault was in the middle of the street, fortunately no one was hurt.

A firefighter pin the scene told me the DC caused them all sorts of problems because with high voltage, high current DC shorts cause a lot more explosive faults than AC. The DC infrastructure was very old, though. And it is not a good last mile distribution method.

Got me thinking. Old elevators in NYC were still using DC motors. Then the infamous 3rd rail of the subway system was about 625 VDC as I recall but also for some reason numbers like 700 or 750 come to mind. Just not sure anymore but for some reason the elevators triggered that thought. I know the last DC Con Ed distribution is gone in NYC but many old buildings use converters maybe for elevators? Damn, as a kid I remember the last of the trolley cars and electric buses.

Ron

 

There was an article about ConEd finally shutting down their DC distribution system around 1998, after all the customers that still needed DC had been issued rectifiers. The DC watthour meters for these services were apparently abandoned in situ as well. I have a picture in my files of one still in place on a wall in a basement somewhere in NYC.

I'd also heard that ConEd got into the AC distribution business by taking over a neighboring company - they did not build any AC infrastructure before that acquisition.

 

The earth's natural frequency has nothing to do, and has no effect, on the frequency used to transmit electricity in power lines or its efficiency.
Why would you think it does?
No significant part of the power-line current travels through the earth.

Just doing some out of the box thinking. Eric Dollard (www.ericpdollard.com) has done some very interesting work on the earth's telluric currents and after googling 'what is the core frequency of earth' and finding out is about 40hz.... you can see where my question got developed.

 

Just doing some out of the box thinking. Eric Dollard (www.ericpdollard.com) has done some very interesting work on the earth's telluric currents and after googling 'what is the core frequency of earth' and finding out is about 40hz.... you can see where my question got developed.

Actually, no. I can't see why.

Also, people named firstname lastname who "publish" random thoughts or plausible thoughts on a website named "firstnamelastname.com" is a hint that the "research" has not been reviewed by anybody and is likely complete nonsense.

And, it is not "out of the box thinking" to be lead down a rabbit hole by someone who has a weird idea. It has several other legal and psychological terms (depending on the context and actions around the events) - but definitely not "out of the box".

Also, search this guy, everything he does seems to be self-published on Amazon, Facebook, podcasts, ... I'm not going to click on his website but he sure is good at being a media hound.

 

Actually, no. I can't see why.

Also, people named firstname lastname who "publish" random thoughts or plausible thoughts on a website named "firstnamelastname.com" is a hint that the "research" has not been reviewed by anybody and is likely complete nonsense.

And, it is not "out of the box thinking" to be lead down a rabbit hole by someone who has a weird idea. It has several other legal and psychological terms (depending on the context and actions around the events) - but definitely not "out of the box".

Also, search this guy, everything he does seems to be self-published on Amazon, Facebook, podcasts, ... I'm not going to click on his website but he sure is good at being a media hound.

I see why you call yourself Mr.Salts. No room for any water. All clogged. No light, no vision and probably a Leo with a calcified pineal gland. If you want to denigh yourself learning from the best, you are on the right path with that attitude.

 

But keep in mind that HVDC (High Voltage DC) transmission is a thing. Some of the larger ones run as a megavolt for really long distances. It is more efficient than AC, and while there are costs to do it, for some uses the costs are easily outweighed by the benefits.

I think DC distribution for residential consumer can also have good impact, I think its very efficient if We use DC lamp, DC water pump, DC electric vehicle charger, and more, and get it directly from solar panel and solar farm

This article is good idea too...

https://electrical.theiet.org/wirin...mber-2021/dc-realisation-in-the-21st-century/

 

I think DC system is good for specific purpose
- Long distance transmission
- Consumer distribution for DC appliance

Its very efficient if we can use DC solar charger directly from solar farm (with DC converter only, without DC - Inverter - Rectifier - DC scheme), also I think its very efficient for motor VFD / VSD, if have direct DC input

 

I see why you call yourself Mr.Salts. No room for any water. All clogged. No light, no vision and probably a Leo with a calcified pineal gland. If you want to denigh yourself learning from the best, you are on the right path with that attitude.

Welcome to the site - please don't misspell MrSalts, No period. Also, I don't call myself that, it's a warning label for other users.

Finally, most people who make open, non-specific posts like yours want an opinion and a discussion. If you only wanted confirmation and coddling, you should have said so.

 

hi Guys,
Please cool down and keep On Topic.

Moderation.

 

I think DC distribution for residential consumer can also have good impact, I think its very efficient if We use DC lamp, DC water pump, DC electric vehicle charger, and more, and get it directly from solar panel and solar farm

This article is good idea too...

https://electrical.theiet.org/wirin...mber-2021/dc-realisation-in-the-21st-century/

The biggest problem with DC is that at high voltages it is much more dangerous than AC and if you lower the voltage to “safe” which is less than 50V, the current requirements go up and You need higher ampacity wire which is more expensive.

 

The history of AC power generating frequencies globally is actually an interesting read.

Growing up NYC my grandfather was a doctor and of well to do means. I still have an old Atwater Kent radio from the Brownstone house in Brooklyn. The cellar of that house for a kid like me was a treasure trove. I discovered a large heavy box with wires. Consolidated Edison originally provided DC current to the Park Slope section of Brooklyn NY. Those who could afford things like a refrigerator the compressors ran on DC. When Con Ed went from DC to an AC distribution grid they gave customers rectifying boxes so they could run their DC refrigerators on the then new AC current.

Niagara Falls hydro electric power generation was originally 25 Hz. Think about AC motors and motor speed. Over the years as we evolved it became apparent that standardization was needed. Even today Japan uses both 50 Hz and 60 Hz power frequencies. The history behind power generation and power frequencies is some interesting reading. There was always something to drive change.

Ron

 

400 Hz may produce a much more annoying sound in transformers and chokes than 60 Hz. If I'm reading the Fletcher-Munson curve correctly, our ears are at least 30 dB more sensitive to 400 Hz than 60 Hz.

 

The biggest problem with DC is that at high voltages it is much more dangerous than AC and if you lower the voltage to “safe” which is less than 50V, the current requirements go up and You need higher ampacity wire which is more expensive.

Yes... its arcing is more dangerous than AC, we need more reliable circuit breakers; my colleague was shorted 110v accidentally and protective masks is burnt, its like welder... very dangerous

 

400 Hz may produce a much more annoying sound in transformers and chokes than 60 Hz. If I'm reading the Fletcher-Munson curve correctly, our ears are at least 30 dB more sensitive to 400 Hz than 60 Hz.

400Hz is a more annoying tone but the OP asked about 40Hz, not 400Hz.

 

hi Guys,
Please cool down and keep On Topic.

Moderation.

Thats true

 

400 Hz may produce a much more annoying sound in transformers and chokes than 60 Hz. If I'm reading the Fletcher-Munson curve correctly, our ears are at least 30 dB more sensitive to 400 Hz than 60 Hz.

Since 400Hz is routinely used in aircraft and shipboard we have plenty of experience with it, so if there is a problem it can't be too bad.

You tangentially remind me of a story, though. At the university I retired from we had an EBL (Electron Beam Lithography) machine which could make nanostructures on silicon wafers using an electron beam. Of course the operation is very delicate and it can be affected by tiny inputs.

After the machine was installed on an isolated concrete slab in the subbasement to eliminate vibration from the building, and power filtering for the AC line was put in place, the first test run was made. It worked perfectly except for a sine wave like wobble in the beam that distorted the lines.

After a bit it became clear it was a 60Hz signal so more filtering was added with no joy. Next sufficient online UPS was added so that the machine ran from batteries instead of the actual line power. On the scope it was very clean power. Still, wobbly lines. It was very frustrating to the researcher who had purchased the, if I recall correctly, half million dollar machine.

Next efforts were made to find an environmental reason. In the process a 60Hz vibration of the floor was detected! It was very low amplitude but the EBL is quite a good vibration meter. After a search a 480V to 120V transformer was located in an electrical room about 60 feet away, bolted to the floor. When this was corrected, the EBL ran smooth as a baby's butt. (FYI, I don't think baby butts are particularly good at etching silicon wafers, it was a limited analogy.)

 

Since 400Hz is routinely used in aircraft and shipboard we have plenty of experience with it, so if there is a problem it can't be too bad.

You tangentially remind me of a story, though. At the university I retired from we had an EBL (Electron Beam Lithography) machine which could make nanostructures on silicon wafers using an electron beam. Of course the operation is very delicate and it can be affected by tiny inputs.

After the machine was installed on an isolated concrete slab in the subbasement to eliminate vibration from the building, and power filtering for the AC line was put in place, the first test run was made. It worked perfectly except for a sine wave like wobble in the beam that distorted the lines.

After a bit it became clear it was a 60Hz signal so more filtering was added with no joy. Next sufficient online UPS was added so that the machine ran from batteries instead of the actual line power. On the scope it was very clean power. Still, wobbly lines. It was very frustrating to the researcher who had purchased the, if I recall correctly, half million dollar machine.

Next efforts were made to find an environmental reason. In the process a 60Hz vibration of the floor was detected! It was very low amplitude but the EBL is quite a good vibration meter. After a search a 480V to 120V transformer was located in an electrical room about 60 feet away, bolted to the floor. When this was corrected, the EBL ran smooth as a baby's butt. (FYI, I don't think baby butts are particularly good at etching silicon wafers, it was a limited analogy.)

Do you think what's disadvantage to 400hz motor against 50/60hz ?, it is copper and power loss is more than 50/60hz motor ?, I think for large industry, if they used 400hz motor and separated generator with 400hz output, I think it can be cost effective

That's my idea long time ago... my client is needs about five dozens of 10HP motor, and I was thinking for make custom request for 400hz motor and generator, but I was abandoned my idea, because I am lack of experience in that area...

 

Do you think what's disadvantage to 400hz motor against 50/60hz ?, it is copper and power loss is more than 50/60hz motor ?, I think for large industry, if they used 400hz motor and separated generator with 400hz output, I think it can be cost effective

That's my idea long time ago... my client is needs about five dozens of 10HP motor, and I was thinking for make custom request for 400hz motor and generator, but I was abandoned my idea, because I am lack of experience in that area...

400Hz might be very good indeed. I don’t really know all the logistics of moving to it, and like all things there will certainly be tradeoffs, but the smaller transformers alone are a really nice concept.