Thane Heins Perepiteia.

[hartiberlin]

All,

Attached is a image of my new air core coil. I have a 8 mm center plastic tube so that I can try out various small cores. The center coil is made of two bi-filar coils. The power coil is made of 0,35mm magnet wire and the trigger coil (for my oscillator) is made of 0,25mm magnet wire. The coil is made egg shaped so that the coil will fit inside the powder Iron core center. The number of turns is 700.

With this coil the oscillator is using 0,1 Amp at 11,97 Volt from the battery. The two secondary coil is not connected to any back looping circuit right now. The open ended voltage was 90 Volts at both coils.

Test number 1:  I started up the oscillator and did look at the amp meter. When I short circuited BOTH coils (or one of them at the time) then I could NOT see any DIFFERENCE in the input current usage!

Next test will be soldering resistors to the output coils and do measurements.

Groundloop.

[EDIT] It is late night now and I will test more tomorrow. First resistor test 470R 5W gave 0,139 VAC over the         
          resistor. Input was 12,50 @ 0,1 A. So over 1 Watt input and nothing something output.
          ( Output: 4,1108510638297872340425531914894e-5 Watt. = 0,00004 Watt.)

Hi Groundloop,
are you sure you did not conect the 2 primary coils wrong,
so they did buck and cancel out in their field ?

Otherwise if not, you have to use at least a ferrite core or an iron
core in it, so you couple the flux into the core.

Also what is the DC resistance of your output coils ?

470 Ohm load resistance might be a bit high.
Try maybe 10 to 100 Ohm to get out more power.

Regards, Stefan.

[Groundloop]

Stefan,

Yes I'm sure. I connected one 470R 5W resistor at each output coil.

The DC coil resistance for the output coils is 33  Ohm for L3 and 37  Ohm for L4.
Lowering the parallel resistor values will only give me lower voltage to measure
and thus even more inaccuracy in the measurement result. If I use a higher resistor
value then the voltage over the resistor will be higher (lighter load on the coils) and
more easy to measure. I will try using some core material in the coil to see if I can
couple more magnetic flux into the core. Will test more this afternoon.

Groundloop.

[Heinstein]

Stefan,

Yes I'm sure. I connected one 470R 5W resistor at each output coil.

The DC coil resistance for the output coils is 33  Ohm for L3 and 37  Ohm for L4.
Lowering the parallel resistor values will only give me lower voltage to measure
and thus even more inaccuracy in the measurement result. If I use a higher resistor
value then the voltage over the resistor will be higher (lighter load on the coils) and
more easy to measure. I will try using some core material in the coil to see if I can
couple more magnetic flux into the core. Will test more this afternoon.

Groundloop.

Dear Groundloop,

Also consider connecting your 2 secondaries in parallel across ONE resistor.
Determine which set up give you the most output - my bet it is this one (above)?
Record data starting at 1k and go down from there 500, 100, 50 25 ohms.
To be really accurate you should also be looking at power factor as well later on perhaps.

Thane

[Groundloop]

Thane,

OK, I will test that also. (Both coils in parallel.) I have seen that loading the output coils will NOT increase the current usage in the input coil so there is still hope. But I agree with Stefan that an air core coil is not transferring enough magnetic flux to the powder Iron core. So I will fill the new egg shaped coil core with Iron wires to get a more powerfull flux with the same input current. Then I will connect both the output coils in parallel to a resistor and see how much output I get. My hope is that the small air gap (due to the tape used) will be enough increase in reluctance for the center coil so that I get no back coupling of the BEMF, even with Iron in that core.

Groundloop.

[Heinstein]

Thane,

OK, I will test that also. (Both coils in parallel.) I have seen that loading the output coils will NOT increase the current usage in the input coil so there is still hope. But I agree with Stefan that an air core coil is not transferring enough magnetic flux to the powder Iron core. So I will fill the new egg shaped coil core with Iron wires to get a more powerfull flux with the same input current. Then I will connect both the output coils in parallel to a resistor and see how much output I get. My hope is that the small air gap (due to the tape used) will be enough increase in reluctance for the center coil so that I get no back coupling of the BEMF, even with Iron in that core.

Groundloop.

Dear Groundloop,

Very good plan.
Keep adding iron into your primary until the current starts to go up it it ever does.
Also try not to assume anything - such as which load is best.
Let the data speak for itself.
I got the most power out a 1 k load but I can't explain why but who cares right now anyway.

Is there any room left on your toroid to add more turns to determine if the output voltage will increase with increased turns with a "static primary" input?

Luc and Steve how are you guys making out?

Cheers
Thane