Ask for help: Bedini SG few simple questions

[yx630514]

A year ago, I followed the standard Bedini SG circuit replication completed successfully.

This is one of my friends do the same circuit existence problems;
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Coil ---- 23,26 (AWG) enameled wire, and about 600 turns;
Coil Core ---- Radio AM antenna ferrite magnetic stick (crushed after the filling into a powder);
Transistor ---- MJE3055T;
Resistance ---- initial state selected 10 ohms (series 1K adjustable resistor);
Magnets ---- Φ10x9mm 6 Ceramic magnets
Battery ---- 10.8V Ni-MH rechargeable batteries;

Problems are as follows:
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1) Use of 1N914 Circuit did not respond, replace the 1N4001 circuit appears the operating characteristic (oscillation coil loud voices), 1N914 should be SG circuit the first choice, but now use it not work. why?

2) resistance temperature is very high! Variable resistor (1/2W) because of high temperatures, burning smoke.

3) Although the circuit oscillations, but the motor still not work.

Thank you to help!
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Xu Yuan

[Sephiroth]

Looking at the datasheet for the 1N914, I don't see any reason why it wouldn't work, so can't comment on that...

There are a few reasons why the circuit may be forced into oscillation. Since you are having trouble with the Emitter-Base Diode, it may have something to do with that... if this diode is not in place or fried then the circuit will be forced into oscillation.

If the base resistance is too high then the circuit will self oscillate and can happen if the pot is fried... I would test the pot just in case...

Make sure the two ends of the trigger coil are wired the right way around... the "positive" side of the trigger coil (the wire coming from the same side as the primary coil wire that goes to the primary battery's positive) should be connected to the base through the resistors.

Also, the magnets might be too small to trigger the transistor with a 600 turn coil... you could try using three double stacked instead of six single stacked...

Hope he gets it going

[Guruji]

Diode

Maybe the 1n914 don't give enough ma for the transistor to switch on.
Thanks

[blackchisel97]

Few things to check

Look at the diagram, trying to understand how current flows. What will cause base resistor to become hot? Your diode reversed or shorted, perhaps? Did you check your coil windings and transistor? With 600 turns of #26 trigger wire you may be pulling 0.2A at 12V from primary source. Not enough to get transistor or any element hot during normal operation. Also, check your potentiometer for continuity. Small pots are easy to damage with disconnected output.
Hope it helps

Vtech

[theremart]

Tricks to test your bedini...

Get your self a small AM radio and put it near you circuit, tune the radio so it it is on an off channel, and try spinning up your wheel. If it is firing, you will hear clicks.

Another trick is to put a very small grain of wheat bulb in the trigger circuit this gives you feedback as to how the circuit is firing.

Verify your resistor is the ohms you believe it is with a meter. I messed up big time on my first build and put in a larger resister than what is needed.

Put in another transistor in place of the present transistor and see if the circuit fires. I do this often to help trouble shoot, change one component at a time till you get the results you are after.

Try swapping the coils leads. Often when you first start the coils are not hooked up properly thus stopping your SSG from running.

Start 4 leads of the coils

Triger Coil wire 1 = T1
Triger Coil wire 2 = T2

Power Coil wire 1 = P1
Power Coil wire 2 = P2


Position 1 as you have it hooked up now.

T1, T2, P1 P2

Try swap Trigger

T2 T1 P1 P2


If fails try swap Power

T2 T1 P2 P1


Then try the last combo

T1 T2 P2 P1


After you change each setup try spinning the wheel to see if you have found the working combination. Hope this helps !

[blackchisel97]

Another trick is to put a very small grain of wheat bulb in the trigger circuit this gives you feedback as to how the circuit is firing.

This is a very good idea It also helps with tuning if you don't have a scope.

Vtech

[yx630514]

Thank you for all the above

I continue to check the circuit, hoping motor to run.

But ,,,,, transistor base resistance now only use 10 ohm, but it is still very high temperatures, very hot! I am even afraid to connect the power to continue the experiment, fear where will explosion.

Xu Yuan

[Sephiroth]

I continue to check the circuit, hoping motor to run.

But ,,,,, transistor base resistance now only use 10 ohm, but it is still very high temperatures, very hot! I am even afraid to connect the power to continue the experiment, fear where will explosion.

Xu Yuan

in fact, a higher ohm base resistor won't heat up as much...

12v / 10 ohms = 1.2 amps

1.2a x 12 = 14.4 watts

so if your base resistance is just 10 ohms, then 14.4 watt pulses could potentially be flowing through that resistor if there is no other resistance in series... but if your pot is only rated for 1/2 watt, then I would guess it has fried (smoke is a reliable indicator )... do you have any higher ohm resistors you could use? around 100 ohm to 300 ohm?

[yx630514]

Your explanation makes sense

in fact, a higher ohm base resistor won't heat up as much...

12v / 10 ohms = 1.2 amps

1.2a x 12 = 14.4 watts

so if your base resistance is just 10 ohms, then 14.4 watt pulses could potentially be flowing through that resistor if there is no other resistance in series... but if your pot is only rated for 1/2 watt, then I would guess it has fried (smoke is a reliable indicator )... do you have any higher ohm resistors you could use? around 100 ohm to 300 ohm?

I have 100-300 ohm resistor, as soon as you say to the experiment.

[Sephiroth]

You should be safe with a 100 ohm resistor to begin with... the motor might run with just that resistor, but will draw alot of current... If you don't have a spare variable resistor then you can add more resistors in series until you find a sweet spot.

[yx630514]

Was conducting an experiment,,,,,

You should be safe with a 100 ohm resistor to begin with... the motor might run with just that resistor, but will draw alot of current... If you don't have a spare variable resistor then you can add more resistors in series until you find a sweet spot.

I judge: transistor base resistance should be the key to determining the motor running, because of this simple circuit there is no other place to adjust.

I plan to start from the 1K resistor in turn reduce the resistance value: 680,510,470,330,220,100 experiment.

However: I just use the 1K resistor experiments when the coil oscillation voice is very sharp, it should be a high oscillation frequency. Important thing is: I have been in the transistor collector and emitter between the connected to a neon lamp, switched on after it is very bright (I use 10-ohm resistor when the neon lamp light to dim a lot), I am afraid, afraid to continue to experiment, Oh,,,,, normal?

There is also a phenomenon: every time power is switched on when the oscillation circuit from the coil can hear the sound (this time using the compass close to the coil core will be apparent reaction), but :2-3 sec later, the sound disappears, again the use of the compass close to the coil core and nothing happens. In other words: This circuit can only be connected to the work of 2-3 seconds after the power stopped working, what is the reason?

Xu Yuan

[ren]

If the resistance is too high it will jump into SELF OSCILLATION. This is the high pitched sound you can hear when the power is connected and the wheel is not spinning.

Try using a 1k pot turned all the way down and a 100 ohm resistor in series with it to the base of the transistor. Wind the resistance up as it comes up to speed, until you find a good value.

Regards

[yx630514]

Coil core material is very important

Thank you for the help

Different resistor values have been used to complete experiment (from 1.2K in turn reduced to 100 ohm), not the slightest improvement in resistance temperature is still very high, motor still not work.

However, the discovery of one phenomenon: the re-winding of a coil, the same 23,26 (AWG) enameled the 600 turn, but the core difference. Because we here can not find R60 welding rod, before coil core the adoption of Radio AM antenna ferrite magnetic stick (crushed after the filling into a powder), new coil around the core to adopt another kind of outside, copper steel electrode, model H13. use of re-winding the coil because core materials of the different, resistance no temperature, coil there is no circuit oscillation voice. But the motor is still not work.

View: iron core material is important, what materials can be used instead of R60 welding rod?

Xu Yuan

[Bit's-n-Bytes]

View: iron core material is important, what materials can be used instead of R60 welding rod?

Xu Yuan

You can use Coat Hanger wire instead of the welding rod.

Bit's

[yx630514]

Experiment success

Thank everyone for appropriate advice

Success reason very simple:
1) did not properly placed the coil and rotor between distance,
2) start-up speed is too small (have not done enough hand-toggle).

Once again thank all helped me the people!
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Xu Yuan