The Underground Lab

[Shanjaq]

Acrylic/Perspex Working?

I'm sure some of us(count me in!) would be highly interested to know how you're creating such intricate Acrylic/Perspex shapes! Please describe the tools/post links describing procedures, etc.!

I've tried routing bits with a high-speed dremel, scoring/snapping and coping saws, but nothing I've made looks quite as polished as what you've created!

[Sephiroth]

I'm cheating and getting the parts fabricated ^_^

[Sephiroth]

Video of the MG-2 before I start messing with the circuit again

YouTube - MG-2 : Pulse Motor Generator

[tjnlsn255]

Mg-2

Hi Seph,

Thank you for the nice MG-2 youtube video.....

I could really use a wiring diagram of your coils, please?

Three bifilar coils on bottom and three (?) coils on top?

What do you mean by parallel and series?

Why not add a little x lube to the bearings it can't hurt, right....LOL

What is your plan to increase the efficiency?

With a brigde rectifier on the secondary output you could feed some of the output back to the primary battery and have a single battery configuration, right?

How is the torque, could you run a pully off the shaft?

Sorry for so many questions but I think you have some great ideas and I am interested in what you are doing.....

Hope and Dreams.....

Tj

[Sephiroth]

No problem. Thank you for asking. It's easier to write about when there are questions to answer

.................................................. .......................................

There are three coils on top of the rotor and three coil on the bottom of the rotor.

There are six bifilar coils altogether (except one of them has a trigger winding so technically one is trifilar).

One winding from each coil is a primary winding used to pulse the rotor and they are all wired in parallel.

the other winding on each coil is a secondary/recovery/generator winding and they are all wired in series.

.................................................. ................................

Lube - even using just a little of my thinnest lubricant slows the rotor down... maybe there is a lubrican that will make the bearings perform better than they do dry but I haven't found one yet (havent tried x-lube though)

.................................................. ...................................

The way the coils are pulsed at the moment isn't very efficient. I want to use single pulses with about 10-20% duty cycle and I want those pulses to be directly on the peak of the sine wave. This will (i believe) produce the biggest mechanical bang for my buck and the back emf will keep current to a minimum.

So the wave would look something like this.




After that, I want to experiment by putting a capacitor on the generator coils which has a very low capacitance so that the voltage generated by the coils is stored and very little current generated. The cap will then be discharged into the charging battery just before the coils fire again, so the sequence of events will look a bit like this.



This bit is hard to explain.

We know that what causes drag with generator coils is current. We also know that energy is transfered to a load with higher efficiency when the impedance of a load is increased.

If I use a relatively high farad cap, say 100uf, then a lot of current will be generated to charge it and that will put alot of drag on the rotor and will also generate heat.

Though if I use a low farad cap, perhaps around 1uf as a guess, then very little current will be generated and the cap will charge up to a very high voltage and very little heat will be generated as well . The impedance of the cap will be so high the the rotor should hardly even notice the load (in theory).

Unfortunately, we know that discharging high farad caps at low voltage charges batteries better than discharging low farad caps at high voltage. But I still think about Bedini's original cap pulser set ups where he did just that...

I don't know what will happen... it's just and experiment so don't keep your hopes up

.................................................. ................................

I don't need a bridge rectifier to loop it back to the front. It can do that already I'm not a big fan of using bridge rectifiers on the recovery windings...

.................................................. ...................................

The torque is good, though it is heavily loaded by the generator so there is not much mechanical energy left to play with.

[citfta]

Pulsing the motor at the right time.

Hi Seph,

I recently built a window motor similar to a Bedini style motor except I have three sets of windings. I was not happy with the way it fired using the trigger windings. I have the magnets alternated north and then south so I was using the full duplex circuit from Rick. My solution for the firing of the pulses was to use some optical switches I got off Ebay. I have also found that Jameco sells them too. I used some old CD's for my discs and mounted one of them to the shaft of my motor. You don't need to cut a slot in them, you just use a razor knife to scrape off the shiny coating in the area you want your optical switch to turn on. I found a disc like tool at the local hardware store that has all the markings on it for laying out any slots in a 360 degree circle. I made up discs with 10 degree slots and 15 degree slots and for real low current draw and low torque I made one with 5 degree slots.

I was able to get it to fire exactly like you are showing in your drawing. I used my scope and was able to adjust the timing by turning the disc on the shaft until I got it where I wanted it. I mounted mine using an o-ring on each side of the disc and left it just a little loose until I got what I wanted and then tightened it down. By the way that is a very nice looking build you have there. Hope these ideas will help a little. See ya, citfta

[tjnlsn255]

Hi Seph,

Thanks for the fast and detailed reply!

-----------------------------------------------------

There are six bifilar coils altogether (except one of them has a trigger winding so technically one is trifilar).

One winding from each coil is a primary winding used to pulse the rotor and they are all wired in parallel.

the other winding on each coil is a secondary/recovery/generator winding and they are all wired in series.
-------------------------------------------

So you have 6 coils in parallel, three on top and three on bottom and 6 coils in series, three on top and three on bottom?

Instead of optical sensors I use a Honeywell Hall device that is inexpensive and allows a ferrite disc to pass through a slot with timing holes and time the trigger that way.....

Keep up the great work and let us know how things go.....

Hope and Dreams.....

Tj

[Sephiroth]

Hi guys,

@Tj - Yep, you've got the idea!

@all - the switching method I am going to use is a 555 monostable multivibrator circuit which will be triggered by a leaf switch comutator. I've tried reed switches but my rotor magnets are too strong, and a Hall would probably have the same problems.

Considered optical switching but figured this would be the easiest way to tune the pulse width May still use optical switching later.

I'll let you know how it goes.

[Sephiroth]

New video from the underground lab

YouTube - Bedini Motors Have NO Torque!

Gone back to the bedini circuit... still can't find any switching method that beats it... but that could just be my engineering skills

[1NRG24Seven]

Is that a standard sized laptop in your pic?...BTW I clicked on the website and got a blank white page, using firefox. Tried it several times with same results. Oops...just realized you stated the site was down...never mind.

Very Impressive work, hope to see your site soon. Thanx

[1NRG24Seven]

No problem. Thank you for asking. It's easier to write about when there are questions to answer

.................................................. .......................................

There are three coils on top of the rotor and three coil on the bottom of the rotor.

There are six bifilar coils altogether (except one of them has a trigger winding so technically one is trifilar).

One winding from each coil is a primary winding used to pulse the rotor and they are all wired in parallel.

the other winding on each coil is a secondary/recovery/generator winding and they are all wired in series.

.................................................. ................................

Lube - even using just a little of my thinnest lubricant slows the rotor down... maybe there is a lubrican that will make the bearings perform better than they do dry but I haven't found one yet (havent tried x-lube though)

.................................................. ...................................

The way the coils are pulsed at the moment isn't very efficient. I want to use single pulses with about 10-20% duty cycle and I want those pulses to be directly on the peak of the sine wave. This will (i believe) produce the biggest mechanical bang for my buck and the back emf will keep current to a minimum.

So the wave would look something like this.




After that, I want to experiment by putting a capacitor on the generator coils which has a very low capacitance so that the voltage generated by the coils is stored and very little current generated. The cap will then be discharged into the charging battery just before the coils fire again, so the sequence of events will look a bit like this.



This bit is hard to explain.

We know that what causes drag with generator coils is current. We also know that energy is transfered to a load with higher efficiency when the impedance of a load is increased.

If I use a relatively high farad cap, say 100uf, then a lot of current will be generated to charge it and that will put alot of drag on the rotor and will also generate heat.

Though if I use a low farad cap, perhaps around 1uf as a guess, then very little current will be generated and the cap will charge up to a very high voltage and very little heat will be generated as well . The impedance of the cap will be so high the the rotor should hardly even notice the load (in theory).

Unfortunately, we know that discharging high farad caps at low voltage charges batteries better than discharging low farad caps at high voltage. But I still think about Bedini's original cap pulser set ups where he did just that...

I don't know what will happen... it's just and experiment so don't keep your hopes up

.................................................. ................................

I don't need a bridge rectifier to loop it back to the front. It can do that already I'm not a big fan of using bridge rectifiers on the recovery windings...

.................................................. ...................................

The torque is good, though it is heavily loaded by the generator so there is not much mechanical energy left to play with.

Have you tried a dry graphite lube used for locks?, its a powder.

[Sephiroth]

Have you tried a dry graphite lube used for locks?, its a powder.

Yep I made a video about a month ago about using graphite in the bearings Tip came from magluvin though

YouTube - Free Wheeling Bearings for Pulse Motors
YouTube - Powdered Graphite Added to Freewheeling Bearings

Yeah, the website is still down but the blog is working...

The Underground Lab : Blog

[Sephiroth]

Is that a standard sized laptop in your pic?...BTW I clicked on the website and got a blank white page, using firefox. Tried it several times with same results. Oops...just realized you stated the site was down...never mind.

Very Impressive work, hope to see your site soon. Thanx

sorry, forgot to mention that the laptop is a netbook so a fair bit smaller than a standard laptop

[ren]

New video from the underground lab

YouTube - Bedini Motors Have NO Torque!

Gone back to the bedini circuit... still can't find any switching method that beats it... but that could just be my engineering skills

Hi Seph,

great work as always, I love these little high speed rockets

I know we've touched on it again, but I really would like to encourage you (again) to try out the half or full bipolar circuit. I think it may be worth looking into, especially if you are looking for top speed. As Ive mentioned, its a little different in function, but well worth a detour and investigation IMO.

As always, I am happy to guide you through the first build of the circuit, if you are interested.

Keep it up

Ren

[Sephiroth]

I'm willing to give it a go but don't have all the componants at the moment... To be honest I can't visualize how a half bipolar circuit performs differently to a standard ssg circuit except that it completely isolates the coil from the circuit during the field collapse... I don't understand how it can produce more mechanical power. I have a feeling it has more to do with the window motor's geometry.

On that note, it seems like a good time to bring this up. I've kind of been keeping it a secret, but the MG2 is really a window motor Yes, it is running on an SSG circuit but the motor's geometry is really an axial window motor.

It will be more obvious when my six magnet n/s/n/s/n/s rotor is finished.