Distance between neo mags on Bedini wheel?

[azura97]

Hi All,
I am currently laying down plans for a rotor and would be appreciative of some advice.
The rotor will be cut from 1/2" Aluminium plate,5 off 2"Dia x 2"L Neo cylinder magnets will be used,the mags will be placed parallel with the axis of the Alloy disc.The magnets will be enclosed in 2" Alloy tubes and locked in place with set screws (so coils will be run not from the edge of the wheel but from the face).
I have two questions.

1/ What distance apart is optimum for these magnets? they are rated 370lb pull and 13,200 Guass. 5 in a circle end on,what pitch circle diameter would be best? I am worried about overlapping fields.

2/ Can i get the same useable radiant spike from the South poles? In using a rotor this way i can use coils on both sides of the wheel and make use of both poles?

Even if i can't use the South poles,i do plan on building a rotor this way as it is easier and cheaper to build a sizeable rotor from plate and tube,less trouble with centrifugal force and mounting heavy magnets.

Thankyou

[wrtner]

Hi All,
I am currently laying down plans for a rotor and would be appreciative of some advice.
The rotor will be cut from 1/2" Aluminium plate,5 off 2"Dia x 2"L Neo cylinder magnets will be used,the mags will be placed parallel with the axis of the Alloy disc.The magnets will be enclosed in 2" Alloy tubes and locked in place with set screws (so coils will be run not from the edge of the wheel but from the face).
I have two questions.

1/ What distance apart is optimum for these magnets? they are rated 370lb pull and 13,200 Guass. 5 in a circle end on,what pitch circle diameter would be best? I am worried about overlapping fields.

2/ Can i get the same useable radiant spike from the South poles? In using a rotor this way i can use coils on both sides of the wheel and make use of both poles?

Even if i can't use the South poles,i do plan on building a rotor this way as it is easier and cheaper to build a sizeable rotor from plate and tube,less trouble with centrifugal force and mounting heavy magnets.

Thankyou

John Bedini is clear that you should not use neos. Use ferrites.

[azura97]

Thanks for your reply wrtner.I am unsure why John would suggest only using ferrites,there seems to be other models about working neos,i am only assuming that the pulling force rating of the magnets has a direct relationship to overall output (work at the wheel and charging output).Do you know if there is perhaps other threads here that discuss the differences between the two in practice?. Regards Mark

[mbrownn]

Neo's can be used although their field is smaller and much more intense so the gap between the magnets would be smaller. Ferrite's are much easier to use and because their field is much larger it is easier to create the scalar poles between the magnets which improves the motoring efficiency.

The job of the magnets is to generate a small current to trigger the transistor and other than that has no effect on the operation of the circuit. It truth they are not even needed as a well tuned circuit can self oscillate; however using magnets to power a motor does give a second output of mechanical energy at little extra cost and improves the COP of the device.

Because the magnets do not have strong interactions with the coil, strong magnets are not needed, this also means the motor power will not be very strong despite having strong magnets.

In conclusion you can use neo's but expect a little more difficulty in tuning for optimum performance.

[Neight]

Thanks for your reply wrtner.I am unsure why John would suggest only using ferrites,there seems to be other models about working neos,i am only assuming that the pulling force rating of the magnets has a direct relationship to overall output (work at the wheel and charging output).Do you know if there is perhaps other threads here that discuss the differences between the two in practice?. Regards Mark

Hello Azura97
I have built the SSG with neos, and can tell you from experience, it is much harder to get it all working right with neos.
the SSG I have working now uses neos, and it is nearly impossible to tune. every time I turn it on, I have to manually tune it. the magnetic pull from the strong neo magnets means I have to give it a decent push to get it running initially, and it wont get up to full RPM without some playing with the potentiometer while it speeds up.

using the ferrite magnets is simply easier to tune, and gives one less possibility for an issue, if it doesn't spin up the first try. it took me a few weeks to get mine running correctly the first go around.

to answer your original question though, you really want to have at least 2 magnet spaces between your magnets with neos.
this gives enough room for clean switching with the transistor. too close and it acts like one single magnetic field, and you wont spin. too far apart and the kick you get from passing the magnet past the coil core wont be strong enough to get the whole thing up to speed, and will ultimately burn more power than needed for the same amount of RPM.
hope that helps,

N8

[azura97]

Dear Mr Brownn and neight,
Thanks equally to both of you for your help,nothing competes with direct experience and i have little of that. You may well have saved us much tuning grief down the road,i had the plan of building a very rigid safe rotor with heavy neos and start from there. I have spent quite some time planning a rotor,i will look into a bulk lot of ferrites,it may be that less money needs to be spent towards magnets now and with a gain in reliability/repeatability!
I will still pursue axial mounting because i can retain barrel magnets in bores more confidently i think,I'm aiming for a high speed torque motor effect. I am still not sure whether i can make use of the South poles on the other side of the rotor? as John appears mostly to make good use of Norths only.

Thanks for the advice.

Best regards

Mark

[John_K]

Mark,

You can use the southe poles as well, you just need to hook the coils up backwards to the north pole coils.

Bedini has demonstrated one of these on EFTV #2.


John K.

Dear Mr Brownn and neight,
Thanks equally to both of you for your help,nothing competes with direct experience and i have little of that. You may well have saved us much tuning grief down the road,i had the plan of building a very rigid safe rotor with heavy neos and start from there. I have spent quite some time planning a rotor,i will look into a bulk lot of ferrites,it may be that less money needs to be spent towards magnets now and with a gain in reliability/repeatability!
I will still pursue axial mounting because i can retain barrel magnets in bores more confidently i think,I'm aiming for a high speed torque motor effect. I am still not sure whether i can make use of the South poles on the other side of the rotor? as John appears mostly to make good use of Norths only.

Thanks for the advice.

Best regards

Mark