Simple Motor

[thaelin]

Aluminum being dia-magnetic, that is why I ask. It will in my book put up a fight against any mag field that comes in contact.

[Matthew Jones]

Ya I thought your talking about the core of the coil, I got confused. Usually an aluminum rotor is OK. As long as the magnets are moving with it.

Matt

[Matthew Jones]

I do not understand this forum model at all. I am trying to update my first post and it will not let me add a title but demand I need one after editing. So I can't post the changes. Anyone have an idea on how to update a post?

Anyway the first thread I forgot in the calculator to divide the RPMS * Magnet number / 60 seconds will give you the frequency. This brings your Henry's up on the coils inductance.

Cheers
Matt

[Matthew Jones]

so little update I had planned on having this thing at least built by now but I had CNC problems, needed new couplings for the motors. Tried one set out that I bought but they weren't correct. So got another set coming and praying they work. Ts motor coming soon.

Matt

[i_ron]

Hi Guys,

Here is the next version of Matt's motor with two coils running on about 4 1/2 watts.

Ron

[Matthew Jones]

Run a lot better for sure. Really quiet.

[Matthew Jones]

I was wondering what the rpm of the motor is? I would guess the next step would be to add a generator coil to it and start harvesting the torque or not, even if all the Gen did was reduce the input further... A Gen could be design to accelerate but then power coming off of it would have to be regulated. These coils tend to produce high voltages but its not end of world to deal with it.

I personally think it would be neat as anything if the motor ran on no current at all. LOL One other thing would be to find away to check the horse power. Mostly you would need a dyno method to find the torque at the shaft. There is leather belt method I think Peter Lindermin published at one time but that was along time ago. There are newer dyno type torque meters for sale out there but maybe there DIY version. Something to look into.

Lets talk about it. I appreciate you i_ron.

Matt

[bistander]

Prony brake dynamometer. Check it out. The other method uses a torque sensor in a shaft coupling set-up, typically a strain gauge device with slip rings or Bluetooth/wifi. Costly. Another diy method uses a shaft mounted slipping friction torque arm pressing or pulling on a scale. You might be able to make a torque arm to shaft coupled by permanent magnets or kinda like a small Eddy current brake instead of friction.

Since you're working with a motor generator, it is possible to use the generator itself as the dynamometer. Might be tricky.
bi

[i_ron]

Hi Guys,

Here is the next version of Matt's motor with two coils running on about 4 1/2 watts.

Ron

Confession time, I have been deceiving myself and you all with too many assumptions. I finally got around to measure the amp draw for the DC DC converter and was shocked. It was drawing over 3 amps! (bread board electronics 15 mA)

So I had been measuring just the out put of the converter thinking it was around 90% efficient --- not so. Mind you I had blown up one 60 volt converter by running it at 63 volts and this one ran so hot I couldn't hold my finger on it, it was so hot.

So back to square one and willing to sacrifice my better DMM I get, without Matt's circuit a draw of 2.65 amps at 11.9 volts. (just a diode to short the back spike) 31.5 watts

With Matt's circuit a draw of 2.5 amps at 11.9 volts, 29.75 watts

Sorry and sad

Ron

[Matthew Jones]

Ya those little converters are rarely over 75% efficient. Well if you were running 5 batteries (60v) you would be somewhere around 26 miliamp. (15 on the board, 7 to the coil.) That's not shabby at all. You got batteries?

@BI thanks for that info. I was racking my feeble mind trying to remember the names of those Dyno's.

@Anyone and Everyone

I had some problems with the CNC had to get them before I cut up to much plastic but finally got everything done. Few little adjustments need to be made But tomorrow I will get the cores together and maybe wind the coils as well mounting the magnets.

TS_Motor.JPG

I also got the circuit designed to run the thing. I am waiting on parts so I can mock it up a bit and make sure I am thinking right. Then I'll order boards. 10 days or something. Initially I am going to test it for while, look for my losses and try to find a way to compensate the system. I built platform so that can receive 2 extra coils. Hopefully I can calculate all the losses and supplement back to system with one coil and do bit of work with other. Just process you have to go through. I am going to post it all good or bad.

Cheers
Matt

[i_ron]

Hi Guys,

While Matt's scheme is not as productive as I had hoped it is not as bad as I thought either.

I put together a birds nest bench supply and the results are:

Conventional diode over the coils --- 42 watts draw

Matt's scheme --- 35 watts draw, not that shabby.

20221206_092324_HDR.jpg


Nice to see my Mastercraft DDM has been idiot proofed to a certain extent for people like me. It has a shutter on the 10 amp setting that only opens when on the 10 amp scale. Once open one can plug in the lead. To turn the meter off one has to disconnect the lead, saves a lot of embarrassment in trying to measure volts on the amp scale.

Ron

[Matthew Jones]

That's not terrible. What's the rpms of your motor maybe we can zero that out. Who knows worth a try... You can always build a coil that doesn't reduce RPMS under load and whatever the makeup of the power you can convert it to what you need. It may or may not be enough but its worth trying,

Matt

[i_ron]

Best RPM seems to be 680 RPM

Ron

[Matthew Jones]

Ah, that's kind of low for the plan I was thinking. If there was a way to add and advance or retard to the timing circuit you could probably get that speed up. If you got up to 1k rpm or better that would be the best range. I think that's your biggest issue now. You might be firing dead center of the coil or maybe before the coil and magnet line up. That's just guess you straighten me out if I am wrong. But the ability to adjust the timing especially when you are try to go faster, is important.

So back to the 1k rpms. What I know to be a fact is 2000 rpms +- on a 8 inch rotor, with iron core coils take ten ohms of wire to accelerate and generate. This I know for a fact. So if that's the case at 1k rpm you would need 20 ohm worth of wire. So something like 1300ft of 22 awg. Now that might produce 600 volt but because of the hertz frequency a relatively small transformer of iron filings or siliconized plates could step that down the useable voltage.

Anyway I am not telling you were to go I am just relaying my thought. Zeroing out that load seems to be the most logical direction to me short of reducing the load.

Let me know.
Matt

[i_ron]

Thanks Matt,

I have an arm that lets me adjust the hall timing.

20221108_111438_HDR.jpg

This is an early photo I thought I had posted but I guess not as it is just the low side switch showing.

And the coils are # 24 wire at 23 ohms so close to 1K feet. So I am coming close to your recommendations already.

Some good information from several sources so will continue to try different things.

Ron