SSG monopole not running

[Carlos Galvis]

Hello ALL, im a new member, i just finished building my monopole using the instructions provided for this experiment as accurately as i could, yet it's still not working, sorry to bother you with this, but i need help, i have rebuilt the circuit 8 times and it seems to be accurate, but obviously there's something im doing wrong... here's a picture/diagram of exactly how i wired my circuit, and another one of the rotor/stator, if any of you can spot the mistake please let me know. wired this way, the coil gets Really hot (above 200F) also the transistor. when i crank the shaft the motor doesn't start, and it seems like the poles are NOT shifting, it stays on attraction mode. the picture/diagram is based on the exact wiring i have on the board, this is my 8th attempt at rebuilding the circuit from scratch with new parts. all parts were tested and so were all the connections... thanks!

[John_Koorn]

Hi Carlos,

It sounds like your transistor is faulty.

To test it, get your meter and set it to the Ohms scale. Take the transistor out of the circuit. Attach the meter leads to any two of the three transistor connections. If the meter reads zero ohms between any two of the transistor connections, it is faulty.


John K.

[Carlos Galvis]

thanks john, unfortunately, that's not it... i found out how to test the transistors a while ago after like the 3rd build , now i check and re-check a million times all the components and connections, i even changed the transistor, the one in the picture is brand new.... it's got to be something else, maybe the wiring... by the way, thanks for teaching me a third way to check the transistors!!... cheers



carlos

[John_Koorn]

Hi Carlos,

I can't tell from your photos if it is a wiring fault. Could you please hand draw what is connected to what and then take a photo of your drawing and post it? (You may even find the fault when you draw it out )


John K.

[Carlos Galvis]

Hi john, thank for your willingness to help, here's the drawing you asked for, its the same as the pic/diagram which still has all the connections (painted them in photoshop!) but maybe this will be more clear, cheers!

[John_Koorn]

Hi Carlos, I can't see anything obviously wrong with that. Can you please disconnect the coils from the circuit and measure the resistance of the trigger and power windings.


John K.

[Gary Hammond]

Hi Carlos and John,

Just checked one of my 2n3055 transistors. According to the drawing, the base and emitter are backwards compared to what I have.

[John_Bedini]

Mono Pole Help For Carlos

Carlos,
I know what John K has said to you , but here is what I see. First the magnets what are they? are they # 8 ferrite magnets or dime store magnets.
Second the coil is not big enough in my opinion, just my opinion. The pot needs to come out of the circuit and insert a 470 to 680 ohm resistor. The circuit looks right.
In the original postings on the school girl motor, as it ran on a 9 volt battery 450 turns on the coil was enough.
If it was me I would use a old solder roll and fill it with wire number 23 for the trigger and number 20 for the power coil.
The solder roll size would be 2.30 inches high and 2 inches diameter, hole diameter of 7.50 filled with the correct welding rod.
John B

[Carlos Galvis]

Thanks to all, first, gary the transistor is seen from above, not below, that is, the cap is on top, so the base and emitter are in the right position... John B. thanks for your reply, the magnets are ceramic from radioshack, they are not very strong... the coil has about 500 turns of #23 and #26 magnet wire, thats all the wire i had... i will try your suggestion to build a bigger coil... do the core welding rods need to be copper coated mild steel?, or can they be bare mild steel?, here's a pic of the batteries i'm using, just in case this is the problem... thanks to all for your help... cheers!

[Carlos Galvis]

Hi john K., i measured the resistance of the coils as you asked... the trigger coil measures 2.6 ohms, and the power coil measures 1.4 ohms...
thanks!

[Ren]

Hi Carlos,

First up.

If there is heat in the coil/transistor when the device is hooked up and not moving then you have an incorrectly wired circuit or short, or bad/faulty component. Full stop. Dont worry about anything else until that is solved. I always put an analogue amp meter inline (series) with the run batteries positive line. When your circuit is correct upon connection you will probably see the meter blip once, ever so briefly. If you conduct current straightaway indefinately you have an unwanted short circuit somewhere.

I just noticed that your protoboard (perforated PCB) is upside down. The norm is to place components on the non copper coated side so that when you turn it over you can solder the legs directly to the indivdual copper coated perforations. Its probably not that much of an issue, but since I cant see under your transistor I cant be sure. It is possible that one of the copper coated rings is touching the base or emitter pin AND also touching the case of the transistor. Incase you are not aware, that whole flat surface (the "brim" of the tophat) is the collector, any connection between this outer shell and the inner pins pretty much = short circuit. Flipping the board over may solve your problem, or alternatively, if soldering is not yet your thing, use no board at all. I see you have made use of the terminal strip to hold your wires, why not use the same method on your base and emitter pins? Quick and easy to change, will make things easier to trouble shoot. You can clamp the E->B diode straight to the pins this way, and use a small nut/bolt/washer assembly on the collector casing to attach your output diode and end of power strand. Make SURE the power strand connects on the ANODE side of the diode/collector case, directly to the collector itself is the best method, but if you leave enough leg on your diode you can connect it to that, its being connected to the collector anyway. All of these methods are for simplifying the process, as you get better you will solder as many connections as possible. Check for any conductive paths under the transistor, a small dab of solder in the wrong place or an off cut in the wrong place is all it takes. If you are uncertain of the pins still google 2n3055 datasheet and you will be able to get a visual reference there. You can do this with any electronic part.



One thing you can try to check if your magnets are strong enough is disconnect your trigger coil and connect it to your multimeter. Try to measure how much voltage is generated when the wheel is spun by hand. Your air gap will have a significant impact on this. 1mm closer can make all the difference sometimes. I have built rotors with such weak magnets on them that you need a string to pull start them, speed is the other factor here, the faster the rotor spins the higher the voltage generated. Now this is not ideal, you should have to only give it a gentle twist to start.

So try measure that trigger coil and let us know how much voltage it can generate. this figure will tell us if your magnets are inducing enough flux to trigger the transistor on. Once you test all the parameters like this something will stick out, you can fix it and you will be on your way.

Keep at it, it makes it all the more worthwhile when it finally takes off. We've all been there, even some of the members who have built this circuit in our sleep still miss parts or hook up wrong from time to time. I know I have.

Regards

[John_Bedini]

Carlos,
I would use copper coated welding rod.
John B

[Carlos Galvis]

Hi Ren, your post was very helpful, thank you very much... so i checked for shorts as you said, but i did it before you posted. you were right! i did have a short, the coil and transistor are not getting hot at all now, the transistor's collector case is not touching the board at all, only the pins go to the other side, but the case is in the air... now nothing is happening, which i assume is an improvement... i did blow up a couple of transistors at the beginning, and one time (this one is amusing), as soon as i cranked the shaft, the wires of the front battery got so hot, that the insulation burned out completely. The circuit seems to be fine now after re-checking a million times, and i will build it again with the board right, i actually like to build it, i'm beginning to memorize it now... i think the problem has to do more with the trigger coil as you and John B. said... i'm waiting on more wire to arrive and the copper coated rods to build a new bigger coil (thanks John B. for the reply)...

thanks for suggesting the voltage read on the trigger coil, didn't think of that... i measured twice, the first time it was reading 0.041V... then i shortened the gap by about 2mm and it read 0.12V... guess its still not enough since it didn't start... heh... and i did crank the shaft as fast as i could by hand as you said... i'm curious to learn how much is needed to start the system... thank you Ren, John B, and John K. for your help, and i will keep at it until i see it run and hope to go into the advanced experiments in good time, i think this system is genius and i appreciate very much the workshop style of teaching that you guys put up here for everyone to learn... cheers

carlos

[Ren]

No problems Carlos, glad I could help.

Feels good to make progress eh? So now you have sorted out your short, you can connect everything up and it doesnt melt your wires. FYI when you melted the wires you must have shorted directly across your battery. In this instance the amount of current that can flow depends on the resistance of the wire doing the shorting, and the CCA or "size" of your battery being shorted. In the beginning if you fear this happening again you can use a smaller capacity battery, say a 9v (disposable) or a 12v battery made up of 8 x AA batteries in series. These batteries when short circuited simply cannot supply large amounts of current and therefore present relatively little danger. Or you can use an inline fuse, which is rated for say, 1 amp, this will work as your "pressure release valve" of sorts. If there is a fault or direct short over 1 amp then the fuse just pops and there is no longer a short.

Once you are up and running, your circuit is all soldered and neat and there is no risk of shorts then you can remove the fuse and use your bigger battery.

As an interesting exercise you should use ohms law to estimate how much current just melted your wire, its a simple and handy equation you will use lots in the years to come. Basically, if you know two of the three variables you can figure out the last with ohms law.

V=IR

V = voltage
I = current
R = resistance.

You know you were using a 12v battery, and just for kicks we will say that it can support infinite current (be thankful that it cant!) So now you need to measure the resistance of the piece of wire that shorted your circuit. Lets just use your power strand resistance on your coil for now. I believe it was 1.2 ohms from memory. So with a little algebraic shuffle you can figure out that @ 12v a 1.2 ohm short circuit will conduct 10amps.

Volts x Amps gives you Watts, in this case 120 watts. Go and have a look at some of your appliances around the house, on there somewhere will be the electrical specs, and a wattage will be listed. So you will get some idea of just how much power you dissipated with that short! Enough to run your ceiling fan perhaps? Or your computer? Now, think about how long your power strand is, and now imagine its only a foot long. Its resistance is going to be nearly non existent. Lets say its 0.01 ohms, the current that can now flow in this short circuit is 1200 amps! @ 12v that is 14400 watts, or 14.4 Kilowatts! I guarantee you will not find ANY appliances around your house that can conduct this type of power!

Of course this is all based on two assumptions:

a) your battery has infinite amperage capabilities (thorium plasma battery style ) Which it does not.
b) your conductor is thick enough to handle the heat generated. (which it was not, it melted the insulation off and if left long enough can actually melt the wire right through.

Your toaster at home operates like this I guess, it short circuits a short length of high resistance wire (nichrome?) till it gets red hot, usually in the vicinity of 1000- 1500 watts is dissipated (it will be written on the toaster somewhere). If the engineer gets his calculations wrong and there are no safety devices installed the potential for fire is very high. All basic forms of heating usually use this principle, pour huge amounts of energy into a short circuited conductor, heat the conductor up, but not so much that it breaks, and channel or focus the heat that radiates from this conductor.

So congrats, you made your first 12v toaster...for a few seconds anyway.

As your building and understanding advances your coils will get lower and lower in resistance, and thus the potential for greater currents to flow increases. Same thing if you put higher voltage batteries into the mix.

If maths aint your thing you can use this simple calculator to get an idea of the potential of current (and fire) to flow through your circuits.

Ohm's Law Calculator

So enough of my ramblings.

Still no triggering happening. Assuming you had your multimeter on the correct settings your readings indicate that there is not enough generated voltage to instigate self triggering. Correct me if Im wrong guys but you generally need just over 1 volt to trigger, it may vary from transistor to transistor. And you are only getting 1/10 of that.

So, you need to adjust your variables (this is why it is recommended to build as close to spec as possible). No matter, we will work with what you have. Here are your options IMO.

a) more turns on the coil, the more there are the higher the voltage will be.
b) more speed out of the rotor (your turning it as fast as you can already by hand)
c) smaller air gap (you saw what a difference this made)
d) stronger magnets (where I think you should go, but still ceramics, no neo's)
e) better core material (not as important as the others in generating voltage, but VERY important in other aspects you will learn about later. Fork out for the R60 welding rod, its worth it.)

All of these play their part in voltage generated. I reckon a change of magnets alone would suffice. If the magnet struggles to pick up a bunch of paperclips it is most likely too weak, some fridge magnets and strip magnets will fall into this category. You dont have to use round ones, but the general rule of thumb is dont go much wider/bigger than the diameter of your core. And enough space for at least 2 of the same magnets to fit in between your magnets on the rotor, not essential, but advisable.

Keep building that circuit, every time you build it try and improve it, make connections shorter, solder directly to the transistor etc. Seems like you've already had a bit of practice thats good.

Let us know how you go.

Regards

[Carlos Galvis]

Ren, thanks for your replies, i am building a new motor from scratch with all the improvements that all of you suggested... the meter setting i used to measure the voltage induced by the coil is VAC... i assumed it was the correct setting, since VDC was reading 0V! also... i could still be wrong because i used a digital meter... would an analog DC meter give me the right answer? i checked around the internet and it seems like the voltage needed to trigger a transistor in general is around 0.6V -0.8V, but it can vary depending on the current flowing through the transistor, i found a few quotes, i don't know if they are accurate:

1: "An output transistor has around 0.6V to 0.8V across the
base/emitter when conducting, but if its supplying a fair
amount of current, the base must be driven by a fair
amount of current, much lower level but still appreciable.

As output stages are nearly always unity gain (no voltage gain)
the actual voltages at the bases are within 1V of the output
voltage, so ~ 51V in = 50V out.

2: "During conduction the potential at the emitter of an NPN device is ALWAYS 0.7V lower than the base (0.7V higher for PNP)
Collector current = emitter current
Base current = collector current/Beta
Combine this knowledge with Ohms law and you have everything you need to start designing and analysing transistor circuits.