Effects of Recirculating BEMF to Coil

[gotoluc]

Luc, I've been around long enough to know when to "throw in the towel" so to speak, so I will graciously bow out of this one. I'm not here to aggravate anyone, and there comes a time when folks just need to find the facts themselves rather than hearing them from others, and that is fine .

I am not 100% certain of what you mean be the quote, but if it is what I think it is, it goes directly against my published numbers up at the top of this page in my findings. Either that or I just don't understand it 

Regards,
.99

PS. Always look forward to your new videos They are top notch!

Hi .99,

if you can help with one more thing I would be gratefull since there is still one thing that no one has explained yet and I'm hopping you can. Why does the sens coil not pickup the rerouted energy and extend the scopes wave form more if it is the case that the energy is extended or what ever it is doing?

Thanks for your time.

Luc

[poynt99]

Hi .99,

if you can help with one more thing I would be gratefull since there is still one thing that no one has explained yet and I'm hopping you can. Why does the sens coil not pickup the rerouted energy and extend the scopes wave form more if it is the case that the energy is extended or what ever it is doing?

Thanks for your time.

Luc

Hi Luc.

Monitoring a coil's voltage does not always indicate what is going on there in terms of its current. The fact that the bottom portion of the coil voltage disappears when the diode is in-circuit, actually does indicate that a conversion is taking place. The conversion is from high voltage/low current, to high current/low voltage. If you zoom in when the diode is in-circuit, you will probably see a negative swing of about -0.65 Volts (from the previous -300V or so), but the current has shot up significantly. This is the indicator that "something" different is happening in the coil that is causing the increased magnetic power.

With no load (i.e. without a flyback diode), the coil sees almost an open circuit during its inductive kickback cycle. The same amount of energy (minus losses) must be conserved, so the coil voltage extends quite high in the reverse direction, but the current is quite small.

When the coil IS loaded during its inductive kickback cycle by placing the diode across it in reverse, the diode creates nearly a short circuit across the coil during this cycle, so the current has no choice but to increase by a large amount. It is this increase of current that you can not see by looking at the coil voltage, but this increased current is what is responsible for the much larger magnetic force being applied to your neo magnet.

Remember with coils, it is current that energizes them and produces a corresponding magnetic field, not voltage. With a heavy enough wire you could produce quite a strong magnetic field with only a few volts, as long as the source can supply a large current.

Hope that helps,
.99

[gotoluc]

Hope that helps,
.99

Hi .99,

yes indeed that helps ... your written explanation was so good that I could actually visualize it as I was reading.

Thank you my friend for all your expertise you have given to this and other topics.

Luc

[wattsup]

Hi .99,

yes indeed that helps ... your written explanation was so good that I could actually visualize it as I was reading.

Thank you my friend for all your expertise you have given to this and other topics.

Luc

Yep, that goes for me too.

[gotoluc]

Hi .99,

I know I said one more question but I just remembered something interesting that happened when I was first testing my large Neo magnet demo board which is in test 2 video.

I had a short happen when I touch a wire to the coil with my soldering iron but still had the power supply of the circuit plugged into the grid. It fried the mosfet and it shot the magnet out of the tube about 3 feet in the air. I was lucky it didn't fall on my head or any other part of me but here is the interesting part. My eyes were quite close to the bottom of the coil where I was going to solder when it happened and I'm quite positive I saw a flame of fire for the first 3 inches of its launch and I thought the coil was on fire but it wasn't the case since my amp meter was in series with the supply capacitor and the 250ma fuse blew before any damage could happen to the coil.

Have you ever heard or know anything about this fire from a sudden strong EMF opposing a very strong permanent magnet pole?

The coil is # 20 AWG, 800 feet long at 8.3 ohms and 63.5 mH. The voltage was 170 vdc from a 330uf cap and limited by the 250ma fuse

Thanks for your time

Luc