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Author Topic: Serious HES derivative project proposal  (Read 29495 times)

bistander

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Re: Serious HES derivative project proposal
« Reply #45 on: February 15, 2023, 08:46:48 PM »
And in this video, a three-phase current supplied from a frequency converter, unfiltered from higher harmonics.
See the difference...
https://youtu.be/jww9Hyhh9G0
p.s. Very bad camera. The good camera in my phone broke.  It would be much better.

Hi kolbacict,
I see the difference. Good job. Another beer for you.
bi

citfta

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Re: Serious HES derivative project proposal
« Reply #46 on: February 15, 2023, 08:51:39 PM »
Hi guys,


Regarding using a VFD powered by DC we need to see what the actual signal looks like.  Here is a video I did and posted in my thread about a moving virtual magnetic field.


https://rumble.com/v1hh4ux-driving-an-alternator-with-rc-speed-controller.html


If you watch that video you will see that my RC speed controller worked great to drive an alternator as a motor.  BUT the pseudo sine wave is actually generated by PWM modulation and did not work well for induction.  So depending on whether or not the output is actually a sine wave a VDF may or may not be a good idea.


Great work guys.  I am following along but will only comment if I feel I have something useful to add.


Carroll

bistander

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Re: Serious HES derivative project proposal
« Reply #47 on: February 15, 2023, 09:50:58 PM »
Hi guys,


Regarding using a VFD powered by DC we need to see what the actual signal looks like.  Here is a video I did and posted in my thread about a moving virtual magnetic field.


https://rumble.com/v1hh4ux-driving-an-alternator-with-rc-speed-controller.html


If you watch that video you will see that my RC speed controller worked great to drive an alternator as a motor.  BUT the pseudo sine wave is actually generated by PWM modulation and did not work well for induction.  So depending on whether or not the output is actually a sine wave a VDF may or may not be a good idea.


Great work guys.  I am following along but will only comment if I feel I have something useful to add.


Carroll

Hi citfta,
Nice demo. Thanks. Of course VFDs use PWM to synthesize sinusoidal waveforms. The voltage will always appear as pulses. But the current is considerably smoother, especially if filters are used or the coils are of high enough inductance. kolbacict's videos show the effects of filters.

The other distinction noted is the RC motor driver has no buss capacitor, that I am aware. The larger VFDs have considerable capacitance directly on or adjacent to the switch bridge. That could be a factor.

What signal was displaying on the scope?
And when you say it didn't work well for induction, what do you mean, or what did you measure to arrive at that conclusion? As in running the former alternator as an induction motor, perhaps?
bi

citfta

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Re: Serious HES derivative project proposal
« Reply #48 on: February 15, 2023, 10:12:16 PM »
Hello Bi,


The signal on the scope was the signal going to one of the 3 legs of the y connected alternator.  As you could see it worked pretty well as a motor.  But when I stopped the rotor to try and draw current from the slip rings as I had done earlier the output from the slip rings was pretty low.  So I concluded that was not a good signal for inducing power into the locked rotor from a virtual rotating magnetic field.


Take care,
Carroll

bistander

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Re: Serious HES derivative project proposal
« Reply #49 on: February 15, 2023, 10:49:13 PM »
Hello Bi,


The signal on the scope was the signal going to one of the 3 legs of the y connected alternator.  As you could see it worked pretty well as a motor.  But when I stopped the rotor to try and draw current from the slip rings as I had done earlier the output from the slip rings was pretty low.  So I concluded that was not a good signal for inducing power into the locked rotor from a virtual rotating magnetic field.


Take care,
Carroll

Thanks for quick reply. I don't think I'd expect induction into the concentric field coil of a Lundell rotor, even if you used a true sinusoidal 3-phase. Kind of a different animal.
Can you reference or link back to what you did previously?
bi

citfta

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Re: Serious HES derivative project proposal
« Reply #50 on: February 15, 2023, 11:12:50 PM »
Hi again Bi,



You're getting forgetful.  We had this discussion a few months ago.  But here is the video I posted before in the other thread showing the induction into the rotor of the alternator.


https://ugetube.com/watch/OTyaKIHaevI6co9


You can go back to the general builders section and look for the thread called " possible idea for virtual magnetic field" to refresh your memory.


Carroll

bistander

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Re: Serious HES derivative project proposal
« Reply #51 on: February 16, 2023, 05:37:51 AM »
Hi again Bi,



You're getting forgetful.  We had this discussion a few months ago.  But here is the video I posted before in the other thread showing the induction into the rotor of the alternator.


https://ugetube.com/watch/OTyaKIHaevI6co9


You can go back to the general builders section and look for the thread called " possible idea for virtual magnetic field" to refresh your memory.


Carroll

You're right citfta, forgetfulness comes along with age. Thanks for the memory jog. I recall now. But rotation with slip rings open circuit meant the rotor iron had induced current and behaved as an induction motor. I'm still having trouble visualizing how that causes varying flux thru the rotor core in the center of the field coil. Getting too off-topic. Might have to scavenge and play with an old car alternator.
bi

kolbacict

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Re: Serious HES derivative project proposal
« Reply #52 on: February 16, 2023, 10:52:59 AM »
Regarding using a VFD powered by DC we need to see what the actual signal looks like.  Here is a video I did and posted in my thread about a moving virtual magnetic field.
I  look from my VFD this. I hoped to see  something better.

something more like sinus. Do you see the same?

bistander

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Re: Serious HES derivative project proposal
« Reply #53 on: February 16, 2023, 03:56:31 PM »
I  look from my VFD this. I hoped to see  something better.

something more like sinus. Do you see the same?

Yet it seemed to produce the RMF.

I see much different PWM with the VFDs that I've scoped. They use a carrier frequency in range of 2 to 20 kHz, or pulses per second.
bi

https://electrical-engineering-portal.com/download-center/books-and-guides/automation-control/induction-motors-pwm-frequency-inverters

kolbacict

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Re: Serious HES derivative project proposal
« Reply #54 on: February 17, 2023, 08:02:52 PM »
Yes you are right. Here is my oscillogram from the current shunt of one of the phases.

p.s. Who deletes my messages here, it's not easy for me to write them in English. >:( :(
It costs you nothing to write thousands.
How kind you are.

SolarLab

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Re: Serious HES derivative project proposal
« Reply #55 on: February 18, 2023, 04:18:29 AM »
 Further to a previous post regarding one Controller approach. This is presented again in
a bit more detail since some experimenters might find it of value as their projects reach a
point where a versatile controller is needed and a "quick to assemble" device might be
handy. [No programming knowledge or experience is required]

Controller Development  (simplified explaination)        Preliminary Rev 0.1 12Sep22

For probably less than $30us a 3 Phase (3 wire - 120deg) or 4 Phase (4 wire - any configuration)
controller can be easily fabricated. It's quite versatile such that a variety of Sequencing and Timing
configurations are available to be tried out when driving a device.

See the attached document for more details, etc.

SL

Attached (pdf):

citfta

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Re: Serious HES derivative project proposal
« Reply #56 on: February 18, 2023, 04:39:48 PM »
Thanks for the PDF SL.  The videos were very good! Is that you in the videos you linked to?  I have some experience programming a picaxe and an arduino so the videos were pretty easy to follow but I can see where they would be very good for someone with no experience in using micro-processors.  The explanations were very clear and even with my experience I learned a few things.  Thanks for posting that helpful information.


Carroll

Cadman

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Re: Serious HES derivative project proposal
« Reply #57 on: February 18, 2023, 05:34:10 PM »
Outstandingly helpful information SL!

Watched the first 4 videos and that was all it took to convince me. I’ll take in the other videos later.

I’ve already downloaded the latest 3 versions of STM32CubeIDE (for Linux, YAY) along with some docs and ordered a couple of NUCLEOF446RE boards from Mouser.

I can’t thank you enough for this

Sincerely
Cadman

citfta

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Re: Serious HES derivative project proposal
« Reply #58 on: February 18, 2023, 05:48:41 PM »
Hi Cadman,


Don't want to derail the thread but what version of Linux do you use?  I have been exclusively on Linux for about 1 and 1/2 years now.  I started with Zorin OS but for the past year have been on LM 20.3.  I'll never go back to Windoze.  Once you get the hang of it Linux is so much better!


Take care,
Carroll

Cadman

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Re: Serious HES derivative project proposal
« Reply #59 on: February 18, 2023, 06:19:50 PM »
Hi Cadman,


Don't want to derail the thread but what version of Linux do you use?  I have been exclusively on Linux for about 1 and 1/2 years now.  I started with Zorin OS but for the past year have been on LM 20.3.  I'll never go back to Windoze.  Once you get the hang of it Linux is so much better!


Take care,
Carroll

Hi Carroll,

lsb_release -a returns Linux Mint 19 Tara.

I haven't had time to perform a proper install but it looks super simple. BTW I almost always make a copy of the whole drive before installing any software that's not in the officai repositories.

Download the release you want, unzip it and run sudo filename.sh command on it and follow the further instructions provided through the console window.. There's an installation guide, but that's really all there is to it.

Gotta run.