Gray Tube Replication

[pranav2010]

ignition coil

hi aaron sir,

in two point system you were used ignition coil

can you tell me how much voltage you were apply to it

if we want vary speed which side we should vary ????????

thank you

[Aaron]

high voltage source

Hi Pranav,

I was using a Mallory Promaster ignition coil. It is somewhere between 50kv and 80kv.... 55k sounds about right. There are several versions of the promaster coil and I'm not sure exactly which one mine is.

That diagram you just posted works every time.

Triggering the high voltage front side with a capacitive discharge with the diode arrangement is the easiest way to make it work even though it will work without the capacitive discharge into the coil.

[pranav2010]

voltage

aaron sir

i want to ask you how much voltage you applying to high voltage side in two point system ???????????


thank you

[pranav2010]

hi crunner

where r u ???????

this is aaron sir's two point system

if you want detail of it go to page no 19 t0 23

you will find all the information

have great day

[pranav2010]

hi crunner

thanks

try this

3500v can jump 1mm gap so if you adjust gap with this proportion

you can solve your problem

have great day

[Ghst]

Shaft Selection

crunner40
I thought that I should bring up the matter of shaft selection. Particularly, watch what material the shaft is made of. I started out using a 3/8" stainless steel shaft in my test motor. I am currently testing with two, 2 inch diameter, 1 inch thick, N50 neodymium magnets on the rotor. I ran into problems with the high voltage jumping from commutator thru the shaft and seeking ground that went to the automotive points on the other end of the shaft. I also noticed that the high voltage would also jump from magnets to the stator coils before the rotor had reached optimum position for the discharge. I know from earlier experiments with the coils on the rotor as Gray used, that its extremely difficult to maintain electrical isolation of the rotor coils when they are mounted on any type of metal shaft. for this reason I removed the 3/8 inch stainless steel shaft from my test motor and replaced it with a 3/8 inch oak (Wood) spindle. But Delrin shafts can be bought off of e-bay for fairly cheep. My wood spindle gives to much deflection. Commutation of these high voltage motors is proving to be a challenge to say the least. I hope this saves you some of the problems that I've had to deal with.

[crunner40]

Hi Pranav,

I am glad that your transformer manufacturer can help you.

Regarding the iron housing, end covers and shaft - you will only know if the iron will give you a problem when you test it. Gray tried different configurations, and it seems that his goal was to keep the amount of "iron influence" near the coils to a minimum. For this reason i went for non-magnetic materials, SS and aluminium, and plastics where possible. Magdude experienced problems with iron brackets near to his coils.

The airgap distance between the electromagnets is critical. It must be as close as you can make it with your machinery. The effect of the magnets drops off very fast as the distance increases. I have made my gap 0.4mm (16 thou"), magdude used a gap of 0.5mm. However the gap must still be wide enough so that the magnets do not collide if there is any deflection of the magnets during rotation.

Re my motor: It is almost 100% fabricated, and only awaits testing before I make the final parts. I tested the initial coils, and am in the process of winding a second coil set with smaller gauge wire for further testing.

Once I can get the tube to fire, I will test it together with the new coils. If all goes well, I will wind and seal all 12 coils and assemble the motor for benchtop testing and measurement.

I am waiting for components at teh moment. It all takes a lot of time, and unfortunately I am busy with work at the moment, so dont have as much time as I would lke..

[pranav2010]

hi crunner

thank you once again

today i had been to the transformer manufacturer

there is E shape wafers are available

i will modify it in a proper shape

and one more think

i used all material is mild steel (body,shaft,end cover)

can you tell is this problematic ?????

you did not tell me is your motor is working or not ????????

have great day

[crunner40]

Hi Pranav,

Yes you can use transformer cores, but you will have to shape them to fit the casing/rotor of your motor, and you will also have to shape the faces to create an even air gap distance.

This would be a lot of work. And you will need access to engineering tools.

If you can you should speak to a transformer manufacturer near to where you live, and give him a dimensional drawing for your cores. He should be able to make them for you. Hopefully at a cost you can afford.

Rgds..

[pranav2010]

core

hi crunner

thanks for the suggestion thank you very much

you are right i facing same problem what you mention

the core wont magnetize fast and strong

c1 capacitor will discharge very fast and only single time

now i am thinking cut 300mm into two part 150mm 150mm

and wind it separately

can i use transformer core ???

already i invest lots of money in motor. my motor is complete but i use all mild

steel material. i think there i mistaken

is your motor working ????? go for aaron sir's two point system

thank you

have a great day

[nat1971a]

Hi guys,

Thought i would report that i did a very quick test last night with adding more magnets to quench the gap. Surprisingly it took 5 ceramic magnets each side of the gap to finally quench the gap. I didnt notice any loud gun shot noises though Mind you i am still using the diode for safety reasons so i might relocate the spark gap to in front of the LV diode and retest.

Cheers
N.

[crunner40]

Magnet core material

Hi Pranav,

Mild steel is not suitable for electromagnet cores, especially in one piece! It will work ok for test purposes only, but will heat up quickly and will be inefficient. This is due to the magnetic flux which builds up in the core. See the comments from TV4FREE (magdude) in the GRAY MOTOR REPLICATION forum.

The most suitable magnetic metal for the core is electrical steel, or ductile iron, or a combination of both as Gray used in his cores. The magnet core must be built out of wafers of metal, all laminated together. Each wafer is coated with lacquer or varnish, so that when they are sandwiched together the lines of magnetic flux are isolated to each wafer. This allows the core to magnetize, and de-magnetize more quickly, and limits the heat build up. There can be electrical contact between each wafer, that is no problem, it is the magnetic continuity that we wish to disrupt.

Transformer cores are built using this method. they are normally laminated out of electrical steel which is the cheapest option, and is the easiest to work with. High quality ductile iron formed of sintered microbeads of iron suspended in a graphite matrix is probably the best option that I know of - but is very time consuming to work with, and requires a bit more thought.

Having magnet cores custom made by a transformer manufacturer should be very cheap in India. I would explore this option. India also has smelters producing products out of ductile iron, and locally you may be able to get the machining done very cheaply.

300mm long magnets will be difficult to wind. When Gray experimented with this he used two shorter magnets mounted close together in series to take the place of one large, long magnet. That makes a lot of sense.

To accommodate 300mm cores, your motor must be a MONSTER..!

Good luck..

[pranav2010]

hi crunner

i am not using permanent magnet on rotor because electromagnet is more powerful

i want to ask you what will happened if i use all material is mild steel.

i used 300mm long magnet core and its not wafer


i am very close to completion

[nat1971a]

Usually in my circuit it is a failed transistor or bad connection as i have built it so poorly as i am more interested in trying multiple setups. but lately it just works.

i havent spent much time trying to perfect anything yet until i find what the secret is to this circuit.

It has been said that grays circuit made a loud bang similar to a gun shot when the cset fired. This sounded very similar to what Tesla said about his disruptive discharge circuit when quenched by powerful magnets. it sounded like a loud pistol shot.

i have noticed in my circuit that the lv diode can make the circuit make a low to medium snapping sound. I think others have noticed similar low level noises. Electrotek mentioned it when he quenched his gap. i propose that this is the secret but the shutoff of the diode isnt fast enough to produce the magic. I believe freeukpower has mentioned before about producing the shortest possibly dc pulse. well it seems to be the shutoff of the one way energy path that is crucial to producing a proper radiant event. this would probably explain why gray patented the vacuum triode or thyratron as it switched off much faster than a diode. interesting enough i was looking at a proposed circuit of how the testatika machine worked which also included a triode vacuum tube. so i am guessing to get the fast switch off that is required then either the magnetic quenching that i have done so far needs to be either more powerful or more focussed or to get the vacuum triode to work. Sort of explains why gray left out the circuit for the vacuum triode. Makes me think i might have to butcher my magnets to look more like Tesla's quenching gap

Anyway my thoughts for the day. I just hope this gets us closer to the so called hoo dooo magic....

[crunner40]

Hi Nat,

I am going to set up the whole project power supply/CSET board again from scratch.

There has to be something simple preventing this from working.

I am making a HV probe for my digital multimeter and oscilloscope as well, this should prevent any more accidents frying the test equipment.

When I followed Aarons suggestions the other day, I actually screwed in the LV rod VERY slowly - looking for the point at which the gap would ARC over. There was no arc, and eventually I had screwed the gap all of the way closed until the two rods were touching. This was a long time after the HV displaced the LV at the cathode of the diode.

Yet on viewing the excellent videos on line - it is clear that the system should have arc'd. Curious huh..?

On the positive side, once I do get it going, I intend to test and measure the different configurations that people have suggested.. ie Aaron, Ghst - to see which is the most efficient. Should be an interesting exercise..