Body
Hi Norman,
For generating high voltage the flyback pulse formed by abruptly stopping the current is used. At input the voltage and current have the same sign meaning energy enters the coil which stores that energy as magnetic field energy. At output the power becomes negative meaning either the voltage or the current has to change sign. If both changes sign then power still enters the coil. Disrupting the current induces the flyback pulse where the voltage changes sign meaning the magnetic field strength is decreasing. The rate of decrease determines the voltage induced. If the energy isn't dissipated like when having capacitance in the circuit the current changes direction after the energy has been stored in the capacitor as electric field energy by charging the capacitor. Discharging the capacitor makes the current change sign while the voltage can't be discontinuous in a capacitor (no jumps allowed). The voltage in a capacitor is like the current in an inductor and the current in a capacitor is like the voltage in an inductor. One can be discontinuous while the other must be continuous by making no jumps. This is what makes them follow each other's tail doing oscillations when connected together and not having enough damping (resistance).
Regards
Ole
---In [email protected], <nwootan@...> wrote :
Sorry Ole, for I have to stick with Tesla on the ALTERNATING CURRENT. https://en.m.wikipedia.org/wiki/Alternating_current https://en.m.wikipedia.org/wiki/Alternating_current
A two stroke outboard motor with magneto running at 3600 RPM has a commutation rate of 60 Hz same as the AC 60Hz line freq. When I was a repair technician for 7 years with Outboard Marine Corp, I got to see a magneto instrumented in a lab with scope leads to enable viewing the voltage and current traces during the magneto cycle. During the 1st step, N-S PMs passing poles 1 and 2 of an E frame armature there was induced a forward current and a positive voltage of up to 450V with a current trace clearly showing the knee of the BH curve indicating the saturation of the iron at peak positive induced voltage/current. As Kone pointed out, this is a short circuited primary winding cause one end of winding is frame grounded and the other end of winding is grounded via the closed breaker points. As you pointed out, current does not like to be stopped and electrons do have inertia so the condenser acts as a shock absorber to take the current surge at point opening and also prevent arcing in the breaker. the accumulated charge in the condenser at circuit opening is up to 450VDC positive. When the breaker points opened there was a straight down, negative going high magnitude negative spike off scope scale. Remember that when the breaker points open the PMs are now inducing a reverse polarity voltage and current into poles 2 and 3 of the E core. I guess that Outboard Marine was correct in using the E frame coil stator for it produced an excellent and powerful ignition source. Since then we have graduated to the Capacitive discharge type of ignition systems.
On 1/25/2019 12:33 PM, onielsen@... mailto:onielsen@... [EVGRAY] wrote:
Hi Norman, Mick,
"...a reverse current is being induced into the iron core coil with the reverse polarity."
The current continues in the same direction while the voltage or tension changes sign. The current can't be stopped or having its direction changed in a jump as it is always continuous. It would be like immediately stopping or changing the direction of a running flywheel. The force required or given off is like the voltage when speaking coils. The voltage or force will be of infinite size if the change happens in an instant. The current starts decreasing from whatever value it has at the disruption. Only how fast is related to the size of the induced voltage (u = L x di/dt) where u is the voltage, L is the inductance of the coil, i is the current and t is time. di/dt is the slope of the current.
Regards
Ole
---In [email protected] mailto:[email protected], <nwootan@...> mailto:nwootan@... wrote :
Mick, first envision a North-South magnetic poles embedded in flywheel. When the North-South magnets bridge the first two poles of the stator (rotation) a forward going current is induced into iron core coil and at same time charges up condenser to max. Important note here is that the impedance of coil is LC matched to the value of the condenser. When the North-South magnets move over to the middle and last poles, breaker points open and at same time a reverse current is being induced into the iron core coil with the reverse polarity, the condenser discharges through coil windings to frame ground. With the condenser being charged via the forward going current, 1st step, when it discharges into coil a reverse current is being induced by moving magnets. In effect you have opposing currents, opposite polarity, (BUCKING-OPPOSED) which cause a miniature magnetic flux annihilation event and a MAGNETO-ELECTRIC, micro EMP event. That is the reason the old magnetos had such a powerful spark even when you turned them by hand at super low RPM. I worked on thousands of them on my magneto test bench. Norm
On 1/25/2019 9:20 AM, Mick mkjekyll@... mailto:mkjekyll@... [EVGRAY] wrote:
Norm,
So this is the same effect from the 3 pole magneto you showed us, when the cap discharges during the collapsing flyback pulse and compresses the delta?
Were three poles used in parallel in order to make sure the iron was fully saturated even at low speed in the old magneto?
On 1/25/2019 9:35 AM, Norman Wootan nwootan@... mailto:nwootan@... [EVGRAY] wrote:
Your quote, feed it a reverse potential as voltage is maximal peaking and you have a mother of an EMP neutral spike on your hands ! Yeeeeeeaaaaah! Hector my friend, you got it exactly right. In all my experience with old time magnetos, this is exactly how the conderser discharge through the primary windings happens with reverse polarity. Bang, you get a sharp crack spark discharge in the bright blue wave lengths. Not a measily orange spark without any zip to it. The 5HP compressor, EMP test I did works this way.
On 1/25/2019 6:35 AM, arkresearch@... mailto:arkresearch@... [EVGRAY] wrote:
If you short a coil current becomes maximal voltage stays lag at zero upon max core saturation , then at short cut off ,voltage becomes leading and maximal as current drop to zero ... basic RF neutral spike dynamics !
feed it a reverse potential as voltage is maximal peaking and you have a mother of an EMP neutral spike on your hands !
(H) other methods are applicable ,,, rotary is best for simplicity ,
---In [email protected] mailto:[email protected], <konehead@...> mailto:konehead@... wrote :
Hi Mick
"would require shorting to saturate the core from passing a magnet"
Did you mean:
"would require shorting to saturate the core from a passing magnet" ?
I don't know something else?
Also wouldn't a shorted coil become rf transmitter not so much an antenna?
Anyways still confused but just half way confused now..
Kone