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I think he made he's own motor as well

PostPosted: Tue Aug 21, 2018 11:27 pm
by Harry Dalek
I don't understand the language but hes work is great
https://viyoutube.com/video/qH5mbzx2hoQ ... %C3%A1nica

Re: I think he made he's own motor as well

PostPosted: Wed Aug 22, 2018 2:52 am
by FlyMario
I can't get enough of this video.

Interesting, I started wondering why 750rpm (12.5). So I started doing some math and came up with. A lot of UK countries have 50hz AC which would make 3000 phase changes in a minute. if you divide that by 4 your will come up with 750 phase changes a minute. So if I am right, they must have had 4 coils may be in the motor that switched using brushes? Does that sound about right?

if that is the reason they chose 750rpm then that is a pretty brilliant use of source voltage to get the speed you need.

Too bad its 60hz in usa :)

Re: I think he made he's own motor as well

PostPosted: Wed Aug 22, 2018 9:22 am
by gary
Harry Dalek wrote:I don't understand the language but hes work is great
https://viyoutube.com/video/qH5mbzx2hoQ ... %C3%A1nica


It appears that he has taken the "guts" out of a bicycle dynamo and transplanted them into a new housing. Bicycle dynamos are often used as synchronous motors by NBTVers (or, at least, used to be).

Re: I think he made he's own motor as well

PostPosted: Wed Aug 22, 2018 10:23 am
by gary
FlyMario wrote:I can't get enough of this video.

Interesting, I started wondering why 750rpm (12.5). So I started doing some math and came up with. A lot of UK countries have 50hz AC which would make 3000 phase changes in a minute. if you divide that by 4 your will come up with 750 phase changes a minute. So if I am right, they must have had 4 coils may be in the motor that switched using brushes? Does that sound about right?

if that is the reason they chose 750rpm then that is a pretty brilliant use of source voltage to get the speed you need.

Too bad its 60hz in usa :)


Well it is generally 8 coils (because both the positive going part of the cycle and the negative part contribute to the rotation), and it is brushless (it is acting as an AC synchronous motor), but otherwise your instincts are correct.

And yes, in the US Nipkow disks are usually run at 900 RPM although at the time (30s) some parts of the US *were* on 50 Hz so 750 RPM was probably used in areas like Los Angeles.

Re: I think he made he's own motor as well

PostPosted: Wed Aug 22, 2018 3:05 pm
by Steve Anderson
Can you imagine the confusion in Japan? Today the SW half of the country has a 60Hz power system, whereas the NW half is 50Hz! Thankfully the voltage is the same at 110/120V.

Much the same as the UK many years ago, different voltages, some AC, some DC. Thankfully it was all unified post WWII with completion sometime in the early '50s to a nominal 240V/50Hz system.

Steve A.

Re: I think he made he's own motor as well

PostPosted: Fri Aug 24, 2018 8:20 pm
by Klaas Robers
Steve, I have a strong idea that Japan has a voltage of 100 V. Years ago when I was in or close to Tokyo I measured it and was surprised that it was 100.0 volts. When I compare this with the Dutch grid voltage of about 230 volts, at this moment it is 233.6 volts, but I see the 0.1 volts changing continuously, but the 1 volts also. Generally it is somewhere between 220 and 240, but on campings I have seen also 200 volts and even 180 volts.

Oh now it is 232.2 volts. Connect your DVM to the power outlet and let the grid surprise you.

But in Japan it was 100.0 volts. How is it possible.....

Re: I think he made he's own motor as well

PostPosted: Fri Aug 24, 2018 9:11 pm
by Steve Anderson
You could be correct Klaas, but just like many countries I think they are trying to standardize Japan's voltages.

When I first moved to Hong Kong in the '80s it was supposed to be 220V - it was usually hovering around 190-200V, today that's all fixed. Kuala Lumpur (Malaysia) seems to have the opposite problem. I admit I haven't been there in over a decade but the mains was often over 260V. Lightbulbs continually burnt out within a few weeks, sometimes days. One hopes they've fixed that too.

Steve A.

Here in Bangkok when the wiring looks like this (below) I'm surprised we have any power at all!

Re: I think he made he's own motor as well

PostPosted: Fri Aug 24, 2018 11:03 pm
by Harry Dalek
That's pretty bad there looks to be no safety procedures in the wiring there ! it reminds me of people using double adapters to the max but this is worse .
Our mains voltage swings a few volts as well.... mechanically made i suppose that's good .
The place where all the wiring is hanging down could be powered just by induction .

Re: I think he made he's own motor as well

PostPosted: Sat Aug 25, 2018 11:59 am
by Steve Anderson
Harry Dalek wrote:That's pretty bad there looks to be no safety procedures in the wiring there !


Not only that, documentation? What's that?

Steve A.

Re: I think he made he's own motor as well

PostPosted: Mon Aug 27, 2018 11:21 pm
by FlyMario
OMG, the Bangkok wiring. I can only imagine the number of deaths a year from electrocution. I don't feel nearly as bad about my circuits with lots of wires all over now.

It looks like my lord and savior The Flying Spaghetti Monster must have originated there.

I hope its ok but I posted this picture on Facebook.
https://www.facebook.com/photo.php?fbid ... pe=3&ifg=1

Re: I think he made he's own motor as well

PostPosted: Tue Aug 28, 2018 10:15 am
by Andrew Davie
FlyMario wrote:It looks like my lord and savior The Flying Spaghetti Monster must have originated there.


Ramen.

Re: I think he made he's own motor as well

PostPosted: Tue Aug 28, 2018 11:44 am
by Steve Anderson
FlyMario wrote:I hope its ok but I posted this picture on Facebook.

No problem. I took the photo so the copyright is mine. But I'm unlikely to make any cash out of it so post away! The area that photo was taken is right in one of the busiest tourist parts of Bangkok - it is a surprise that I've never seen any reports of electrocution in 23 years of being here.

The wiring in India is just as bad!

Steve A.

Re: I think he made he's own motor as well

PostPosted: Tue Aug 28, 2018 6:51 pm
by Andrew Davie
Steve Anderson wrote:it is a surprise that I've never seen any reports of electrocution in 23 years of being here.


When my wife visited Thailand recently and saw the mess of wiring, she said she could hear the whole thing "humming" or "buzzing" as she walked past.

Re: I think he made he's own motor as well

PostPosted: Tue Aug 28, 2018 8:29 pm
by Steve Anderson
Yep, especially when it's humid. I've seen broken HV cables where the exposed end is arcing to the pavement - I gave it/them a wide berth.

A regular occurrence is transformers on power poles exploding, similar to the ones you see on US TV and that in the photo above. You're working away and suddenly the power goes off - a short time after you hear a 'BANG', maybe half a second (the speed of sound and distance).

The transformer that feeds this house is about 30m away. One evening at around 9PM it exploded. I thought, "That's it until tomorrow afternoon at best." But no, within 30 minutes a crew isolated the whole village, disconnected the old transformer and a replacement arrived. A crane hoisted the old one out and in went the replacement. Power was back on at about 1AM - you could tell they had done this before!!

The one that feeds this house and many others is rated at 500kVA - not to be mucked around with! The one in the photo I'm guessing is 1MVA (1000kVA).

Steve A.