Reactive power - Reactive Generator research from GotoLuc - discussion thread

[gotoluc]

Hi Poynt and anyone else interested.

I made a video of the Bifilar Toroid under test and found another coil which happen to be the same DC resistance 0.6 Ohm as the toroid and connected it to compare the two at different frequencies.

Link to video: http://www.youtube.com/watch?v=IinbBzcjojY&feature=youtu.be

I'm not claiming anything, I just find it interesting and would be interested to know what can cause this.

Thanks for your time

Luc

[poynt99]

I don't know for certain Luc, but if I was to guess, I would say that your bifilar connection may be in error, and your toroid is actually a small capacitor, not an inductor. Can you measure a DC resistance between those two leads?

Your toroid seems to be working like a capacitor; low current at low frequency, higher current at higher frequency.

[Magluvin]

Hi Poynt and anyone else interested.

I made a video of the Bifilar Toroid under test and found another coil which happen to be the same DC resistance 0.6 Ohm as the toroid and connected it to compare the two at different frequencies.

Link to video: http://www.youtube.com/watch?v=IinbBzcjojY&feature=youtu.be

I'm not claiming anything, I just find it interesting and would be interested to know what can cause this.

Thanks for your time

Luc

Hey Luc

The 2 coils have the same resistance, but they have way different inductance, and capacitance.

The toroid has more inductance and capacitance. That coil may not allow much current above 100 or even 200hz let alone 1khz as a coil alone, not in resonance.   Does your sig board do sweeps? I might think that there is a lower than 4mhz resonant freq for the toroid, by the looks of it anyways, especially if it is series bifi.

If it really is set as series bifi, and it really only conducts well at around 4mhz, then the other coil will be way above that before it rings.

Mags

[gotoluc]

I don't know for certain Luc, but if I was to guess, I would say that your bifilar connection may be in error, and your toroid is actually a small capacitor, not an inductor. Can you measure a DC resistance between those two leads?

Your toroid seems to be working like a capacitor; low current at low frequency, higher current at higher frequency.

Hi poynt,

there's no error in my bifilar connections!  I've been winding series bifilar for some years, so that's not a possibility. Also, I can measure DC resistance between leads and posted it above ( 0.6 Ohms ) in my post with the video.

I would agree that it's an Inductor behaving like a capacitor!... that's why I wound this toroid to test the possibilities.
Maybe we can make Inductive Capacitors... what do you think about that?

I'll be working on this and posting videos.

Luc

[picowatt]

Hi Poynt and anyone else interested.

I made a video of the Bifilar Toroid under test and found another coil which happen to be the same DC resistance 0.6 Ohm as the toroid and connected it to compare the two at different frequencies.

Link to video: http://www.youtube.com/watch?v=IinbBzcjojY&feature=youtu.be

I'm not claiming anything, I just find it interesting and would be interested to know what can cause this.

Thanks for your time

Luc

Luc,

All three of the resistors in your video are wirewound.

The LVR series is specified as "low inductance", but the actual inductance is not given in the data sheet.

The RS series was available in a "non-inductive" wind, but they would have then had the "R" replaced with an "N" (i.e., "NS" series), so I would consider the RS inductive.

Be aware that a lot of manufacturers consider anything under 100nH as being low or non-inductive, which, for low value resistors used at higher operating frequencies, is way too much inductance.  The best I have been able to find are Caddock units specified as 4nH when measured .1" from the resistor body (which adds 0R1 at 4MHz).

A rough estimate to follow for a "normal" sized straight wire is ~20nH per inch, which is ~0R5 of reactance at 4MHz.  Therefore, a 0.2" length of wire is ~0R1 at 4MHz.  That's means that just 0.1" of wire at each end of a "non-inducive" 0R1 resistor will add another 0R1 of reactance to that resistor at 4MHz (effectively doubling its value).  A six inch cliplead has about 3R of reactance at 4MHz.

Don't you have some small wattage (1/4W or 1/2W) carbon or MF resistors that you can neatly parallel (very short leads) to make a low value CSR?  Putting resistors in parallel (with very short/neat leads) also places their inductance in parallel which reduces the total inductance. 

Using a larger value resistor for your CSR (=/>1R) will also reduce CSR measurement errors due to inductive reactance.  Roughly speaking, assuming zero inductance resistors, a 0R1 CSR with 0.1" leads is 0R2 at 4MHz (100% error), a 1R CSR with 0.1" leads is 1R1 at 4MHz (a 10% error), and a 10R CSR with 0.1" leads is 10R1 at 4MHz (a 1% error).

PW