Sparking problem

[Penelope Stopit]

O mage said:

The 2 volts in the magic trick is being stored by the coils in the core as magnetism and so is invisible to your meter.....Appears Disappears now you know how the trick is done you can open your bonnet and amaze your friends and family with it you could wave a magic wand over it for full effect and for the grand finalle you can present them with a hot pot of tea boiled in a jug by the coil itself. Imagine the look on their faces as they revere your magical prowess

Nobody will understand the above

You are unable to explain how the coil supply drops from 12.5 volts to 10.5 volts when the coil negative is jumped to battery negative and the 12 volt ignition system is operating correctly with a fully charged battery

The voltage shouldn't and doesn't drop by 2 volts in a correctly functioning ignition system

The below post doesn't explain it

O mage said:

Volts disappear and heat appears shall we just call it a magic box. The secondary in these automotive tesla coils is connected to the primary at the mid point of the primary inside the casing of the device you are testing. Does that help.?

[Penelope Stopit]

pk500 said:

Yes I get ph mail go to my email address

Ok then, noted for the future

[O mage]

Penelope Stopit said:

O mage said:

The 2 volts in the magic trick is being stored by the coils in the core as magnetism and so is invisible to your meter.....Appears Disappears now you know how the trick is done you can open your bonnet and amaze your friends and family with it you could wave a magic wand over it for full effect and for the grand finalle you can present them with a hot pot of tea boiled in a jug by the coil itself. Imagine the look on their faces as they revere your magical prowess

Nobody will understand the above

You are unable to explain how the coil supply drops from 12.5 volts to 10.5 volts when the coil negative is jumped to battery negative and the 12 volt ignition system is operating correctly with a fully charged battery

The voltage shouldn't and doesn't drop by 2 volts in a correctly functioning ignition system

The below post doesn't explain it

O mage said:

Volts disappear and heat appears shall we just call it a magic box. The secondary in these automotive tesla coils is connected to the primary at the mid point of the primary inside the casing of the device you are testing. Does that help.?

It's not that i am unable to explain it i have done in many ways. The problem is YOU are unable to understand it. you have no idea whats going on in the coil so to you it's a magic box.

[adam quantrill]

Penelope Stopit said:

How could you have possibly been back through the posts?

If you had read the above posts that I've re-posted here in this post, you wouldn't be asking all these questions

Err, by reading them? And ignoring anything not posted by BigFish_74, which ends around page 4, so not really a lot of actual facts to work from. One that I missed though on the first reading is that the car might be 1988.

Anyhow, if such a post exists where Mr Fish re-measured the battery voltage explicitly at the same time the earth jumper was applied, and then posted the value measured, then please point it out.

Anyhow I wasn't asking a question, I was pointing out a small error in your logic.

Edited by adam quantrill on Tuesday 16th June 17:29

[O mage]

O mage said:

Inside the device you are testing there are two coils wrapped around an iron core as the coil is turned on via the secondary terminal being switched to earth then voltage is pulled into the primary and secondary coils and so electromagnetism is built up in the iron core. This magnetic field then breaks down when the coil is switched off through the secondary. when it collapses a massive voltage is released from the core and down the king lead.

This action produces heat and the circuit should not really be over timed as it is being whilst doing the test

In operation the coil is only triggered for milliseconds.

I hope this helps you understand what is happening in the circuit you are testing.

^^^^^^^
This
Now go and consult your little books and try to understand what is going on inside an ignition coil. As that is what you are measuring!

Or don't, Then you must call it a magic box that you don't understand and move on to the next step.

Edited by O mage on Tuesday 16th June 18:10

[Penelope Stopit]

adam quantrill said:

Penelope Stopit said:

How could you have possibly been back through the posts?

If you had read the above posts that I've re-posted here in this post, you wouldn't be asking all these questions

Err, by reading them? And ignoring anything not posted by BigFish_74, which ends around page 4, so not really a lot of actual facts to work from. One that I missed though on the first reading is that the car might be 1988.

Anyhow, if such a post exists where Mr Fish re-measured the battery voltage explicitly at the same time the earth jumper was applied, and then posted the value measured, then please point it out.

Anyhow I wasn't asking a question, I was pointing out a small error in your logic.

Edited by adam quantrill on Tuesday 16th June 17:29

You've not quoted my full post and that makes a big difference

My full post makes it obvious that the coil was to be earthed, ignition switched on, battery voltage measured

The below was included

Penelope Stopit said:

When having 12.5 volts @ the battery and 10.5 volts at the coil

What voltage is there at the ignition switch supply in and ignition out?

It's obvious that the coil needed to be earthed to read the above voltages (12.5 volts @ the battery and 10.5 volts at the coil)

Fortunately Bigfish read the above

There was no error in my logic, there was an error in my explaining of the test in not mentioning to check battery voltage then coil supply voltage within seconds of one another

If there was any misunderstanding, my later post would have put things right

Have no idea what measurements Bigfish ended up taking or what was found....should I ?

[Penelope Stopit]

O mage said:

Penelope Stopit said:

O mage said:

The 2 volts in the magic trick is being stored by the coils in the core as magnetism and so is invisible to your meter.....Appears Disappears now you know how the trick is done you can open your bonnet and amaze your friends and family with it you could wave a magic wand over it for full effect and for the grand finalle you can present them with a hot pot of tea boiled in a jug by the coil itself. Imagine the look on their faces as they revere your magical prowess

Nobody will understand the above

You are unable to explain how the coil supply drops from 12.5 volts to 10.5 volts when the coil negative is jumped to battery negative and the 12 volt ignition system is operating correctly with a fully charged battery

The voltage shouldn't and doesn't drop by 2 volts in a correctly functioning ignition system

The below post doesn't explain it

O mage said:

Volts disappear and heat appears shall we just call it a magic box. The secondary in these automotive tesla coils is connected to the primary at the mid point of the primary inside the casing of the device you are testing. Does that help.?

It's not that i am unable to explain it i have done in many ways. The problem is YOU are unable to understand it. you have no idea whats going on in the coil so to you it's a magic box.

Please re-post where you have explained ?

I know you haven't explained, you know you haven't explained, why comment that you have ?

Am only bothering to ask because you have posted that my supplied information is incorrect and I like many others know that it is not

You have taken much time in attempting to convince others that I don't understand how a simple circuit works

You have posted much nonesense in your attempts to prove you are correct

Explain the following for everyone's benefit

Why is it that the information that I have posted, apart from it being in my head, is to be found at numerous websites and within many printed articles ?

The very same information has been used for many years throughout engineering colleges and universities and has stood the test of time

The information that I have posted is fact

What you have posted about the vanishing of 2 volts can't be found and you can't explain it

There have also been occasions when you have posted in a child like fashion and added abbreviated swear words to a post

Right now I am looking at a very good article that proves you are posting nonesense to this topic

Should you ask me how the above article is proof of your nonesense, I would comment that there are thousands of similar articles to be found

There are no articles discussing what you have posted due to it not being possible....If it doesn't take place it can't be discussed

I very much doubt you will explain

Rightly or wrongly I doubt you are being sincere, you may have been motivated by something or other, you did post to another topic that I was posting to and seemed to be attempting to create the same sort of environment as what you have achieved here

[O mage]

O mage said:

O mage said:

Inside the device you are testing there are two coils wrapped around an iron core as the coil is turned on via the secondary terminal being switched to earth then voltage is pulled into the primary and secondary coils and so electromagnetism is built up in the iron core. This magnetic field then breaks down when the coil is switched off through the secondary. when it collapses a massive voltage is released from the core and down the king lead.

This action produces heat and the circuit should not really be over timed as it is being whilst doing the test

In operation the coil is only triggered for milliseconds.

I hope this helps you understand what is happening in the circuit you are testing.

^^^^^^^
This
Now go and consult your little books and try to understand what is going on inside an ignition coil. As that is what you are measuring!

Or don't, Then you must call it a magic box that you don't understand and move on to the next step.

Edited by O mage on Tuesday 16th June 18:10

[adam quantrill]

Penelope Stopit said:

It's obvious that the coil needed to be earthed to read the above voltages (12.5 volts @ the battery and 10.5 volts at the coil)

Fortunately Bigfish read the above

There was no error in my logic, there was an error in my explaining of the test in not mentioning to check battery voltage then coil supply voltage within seconds of one another

If there was any misunderstanding, my later post would have put things right

Have no idea what measurements Bigfish ended up taking or what was found....should I ?

I don't like to quote entire posts because it bloats the thread, but as you insist...

Another logical error is in your deduction that his reply quoted above was an acknowledgement of your assumption.

At no point did Mr Fish actually state that the 10.5V measurement was taken at the same time as the 12.5V measurement in his posts. You haven't produced a post that I've missed, where he said that he re-measured it at the same time.

So the poor battery has not, in my mind, been eliminated from the list of suspects. Which is why I raised the point, as I like to keep an open mind.

I'm not sure why you're so against the idea, as you seemed to be coming around to the possibility a few pages back yourself.

Anyhow the 1988 date is quite significant as around that time TVR were introducing the other layout for the ignition system, you know, the one I pay "homage" to, as it's in my car, so it's worth bearing in mind too.

[Penelope Stopit]

adam quantrill said:

I don't like to quote entire posts because it bloats the thread, but as you insist...

Another logical error is in your deduction that his reply quoted above was an acknowledgement of your assumption.

At no point did Mr Fish actually state that the 10.5V measurement was taken at the same time as the 12.5V measurement in his posts. You haven't produced a post that I've missed, where he said that he re-measured it at the same time.

So the poor battery has not, in my mind, been eliminated from the list of suspects. Which is why I raised the point, as I like to keep an open mind.

I'm not sure why you're so against the idea, as you seemed to be coming around to the possibility a few pages back yourself.

Anyhow the 1988 date is quite significant as around that time TVR were introducing the other layout for the ignition system, you know, the one I pay "homage" to, as it's in my car, so it's worth bearing in mind too.

This was posted early on in the topic

Penelope Stopit said:

When having 12.5 volts @ the battery and 10.5 volts at the coil

What voltage is there at the ignition switch supply in and ignition out?

Bigfish acknowledged the post with the following

Bigfish_74 said:

Penelope Stopit said:

When having 12.5 volts @ the battery and 10.5 volts at the coil

What voltage is there at the ignition switch supply in and ignition out?

From my above post any possible misunderstanding would have been sorted

It can be seen that I'm suggesting to carry on taking measurements while the coil is earthed

I later posted the following

Penelope Stopit said:

Have you carried out the volt-drop tests as posted above and reposted here?

Once you get that coil supply sorted you will be able to move on to testing the HT side

Have you considered supplying the coil with a fused 12 volt supply directly from the battery using a heavy enough cable and also then measuring the voltage at the coil?

---

Sorry, didn't even consider that you might not be aware of how to test for where the volt-drop is

Visual checks are ok but something is often overlooked, a visual check won't show what part of the circuit is causing the problem

With ignition on and coil supply connected, all coil negative cables removed and coil negative earthed

Using a voltmeter,

Connect the voltmeter across each side of a fuse to be tested

Connect the voltmeter between the battery supply into the ignition switch and the ignition supply coming out of the ignition switch

Connect the voltmeter between ignition switched supply from ignition switch to other end of cable at fuse

Connect the voltmeter between ignition fuse and coil positive

And so on and so on, rev counter and.........

The volt-drops will be shown by the voltmeter

DON'T OVERHEAT THE COIL, KEEP SWITCHING OFF BETWEEN TESTS

This is a good read https://www.fluke.com/en-us/learn/blog/automotive/...

Any possible misunderstanding is now definitely sorted out

Now this does get better, days ago I misread this following post from Bigfish, I hadn't realised he was answering my above post that contained

Have you considered supplying the coil with a fused 12 volt supply directly from the battery using a heavy enough cable and also then measuring the voltage at the coil?

Bigfish_74 said:

I thought that but didn't like the idea of heating the coil up again and again. I had done a direct test to the coil and no drop, so as you say I do need to locate where the drop is. Just rebuilding the ignition relay as that was a mess.

Regarding your comment about keeping an open mind....Me too

You think battery problem and are free to do so

I don't think battery voltage was a problem, 12.5 volts is a sign of 90% charged and Bigfish has sorted engine earth leads out plus never mentioned a slow cranking problem

You do know that a battery that will happily crank an engine over will not drop to 10.5 volts when switching the ignition on

adam quantrill

To help me answer your post I've needed to read through the first few pages of this topic and noticed I had misunderstood a Bigfish post, I hadn't realised it was a reply to my earlier post. All posted once again below

Penelope Stopit said:

Have you considered supplying the coil with a fused 12 volt supply directly from the battery using a heavy enough cable and also then measuring the voltage at the coil?

Bigfish_74 said:

I thought that but didn't like the idea of heating the coil up again and again. I had done a direct test to the coil and no drop, so as you say I do need to locate where the drop is. Just rebuilding the ignition relay as that was a mess.

adam quantrill Thank you so much for all your input, how on earth did i miss the above post

O mage Is going to be delighted with this

Cheers, have a good evening, most important of all stay safe

[O mage]

Im not the least delighted im astounded at the length you are going to. The last time your theory broke down you began to blame the( not present because he has 12v) ballast resistor. And now you have resorted to taking things out of context and spam posting.

Just admit you don't know what the magic box is doing when you test it.

[blitzracing]

Well its been entertaining if nothing else. Should anyone have not fallen asleep by now here is what is going on inside the coil, to cut through some of the voodoo about magic boxes and stored voltages (???).

A DC voltage is applied to the coil primary by grounding through the points or amp. Now as the coil comprises of many turns of copper wire around a metal core as mentioned its referred to as an inductor. The unique thing about this is when you apply a voltage and a current flows, the magnetic field it produces cuts through its own coil windings acting like a generator and produces a back voltage that pushes back against the applied voltage, known as reactance and limits the current flow. This delays the magnetic fields growth rate,(dwell period) but dies away once the magnetic field peaks out and is no longer changing. At this point the coil has reached its full magnetic storage capacity, and the current still flowing in the primary simply becomes heat depending on the copper wires resistance and that's why you don't leave it switched on for long. The magnetic field strength can be calculated from the number of peak amps flowing, and the number of turns, that affects its resistance and therefor the current. A high power coil (say 2 ohms) has fewer primary turns with thicker wire, and this reduces the back emf generated in the primary so the coil can reach its peak magnetic field faster, (its flux level) but at the cost of a higher current drawn.and this reduces your dwell angle (or coil charge time). This is really important on a V8 as you only have a few milliseconds between firing cycles at high RPM. The available peak HT voltage drops quite sharply on the RV8 above about 4000 rpm as the dwell becomes shorter than the required coil charge time, but its over engineered enough to still fire the plug.


Now the point of firing- the points or ignition amp now disconnect the ground side of the coil so the primary current stops, causing the magnetic field to collapse and produces a big voltage spike in both the primary (150 to 300 v) and secondary coil winding (up to about 30 kv) , but it needs a path to ground to complete the circuit. This is done with a capacitor that basically forms a low resistance path to what is an AC waveform to ground, whilst not affecting the DC that is applied to the coil. It also has the effect of storing a bit of the coils primary voltage that it then pushes back into the coil, that then pushes back again, and affect known as ringing that you can see with a 'scope.

The secondary voltage will simply keep rising as the magnetic field collapse to the point the plug fires, at which point the plug resistance drops sharply as the arc occurs to a point the arc just burns- typically 5 to 15kv depending on the combustion pressures and spark gap and the burn time will depend on the peak flux / windings in the coil and the resistance of the HT leads. The leads resistance acts to slow the discharge of the coil,(collapse of the magnetic field) to increase the burn time, and also suppress radio interference. By controlling the rate of collapse of the field, you also controls the spikes generated in the coil primary- to typically 150v. Put copper HT lines on a car and you will see double that, as the HT path resistance is too low and the burn time will become shorter, and spark hotter. The burn time will also be cut short on a high revving V8 due to the requirement for enough dwell period to recharge the coil.

As you can see its quite complex when you drill down into whats going on but I hope this helps :-)

[O mage]

blitzracing said:

Well its been entertaining if nothing else. Should anyone have not fallen asleep by now here is what is going on inside the coil, to cut through some of the voodoo about magic boxes and stored voltages (???).

A DC voltage is applied to the coil primary by grounding through the points or amp. Now as the coil comprises of many turns of copper wire around a metal core as mentioned its referred to as an inductor. The unique thing about this is when you apply a voltage and a current flows, the magnetic field it produces cuts through its own coil windings acting like a generator and produces a back voltage that pushes back against the applied voltage, known as reactance and limits the current flow. This delays the magnetic fields growth rate,(dwell period) but dies away once the magnetic field peaks out and is no longer changing. At this point the coil has reached its full magnetic storage capacity, and the current still flowing in the primary simply becomes heat depending on the copper wires resistance and that's why you don't leave it switched on for long. The magnetic field strength can be calculated from the number of peak amps flowing, and the number of turns, that affects its resistance and therefor the current. A high power coil (say 2 ohms) has fewer primary turns with thicker wire, and this reduces the back emf generated in the primary so the coil can reach its peak magnetic field faster, (its flux level) but at the cost of a higher current drawn.and this reduces your dwell angle (or coil charge time). This is really important on a V8 as you only have a few milliseconds between firing cycles at high RPM. The available peak HT voltage drops quite sharply on the RV8 above about 4000 rpm as the dwell becomes shorter than the required coil charge time, but its over engineered enough to still fire the plug.


Now the point of firing- the points or ignition amp now disconnect the ground side of the coil so the primary current stops, causing the magnetic field to collapse and produces a big voltage spike in both the primary (150 to 300 v) and secondary coil winding (up to about 30 kv) , but it needs a path to ground to complete the circuit. This is done with a capacitor that basically forms a low resistance path to what is an AC waveform to ground, whilst not affecting the DC that is applied to the coil. It also has the effect of storing a bit of the coils primary voltage that it then pushes back into the coil, that then pushes back again, and affect known as ringing that you can see with a 'scope.

The secondary voltage will simply keep rising as the magnetic field collapse to the point the plug fires, at which point the plug resistance drops sharply as the arc occurs to a point the arc just burns- typically 5 to 15kv depending on the combustion pressures and spark gap and the burn time will depend on the peak flux / windings in the coil and the resistance of the HT leads. The leads resistance acts to slow the discharge of the coil,(collapse of the magnetic field) to increase the burn time, and also suppress radio interference. By controlling the rate of collapse of the field, you also controls the spikes generated in the coil primary- to typically 150v. Put copper HT lines on a car and you will see double that, as the HT path resistance is too low and the burn time will become shorter, and spark hotter. The burn time will also be cut short on a high revving V8 due to the requirement for enough dwell period to recharge the coil.

As you can see its quite complex when you drill down into whats going on but I hope this helps :-)

I agree but i doubt your explanation will do any good for some
I know how it works it's just that others on here definitely don't and shouldn't really be preaching if they don't understand the device being tested and what effect it has on the voltages when measuring across the two terminals.

[adam quantrill]

Thanks Mark, yes indeed at 6000 rpm the sparks are coming at 5ms intervals, so the coil must be pretty much fully energised and in steady state within say 10ms of connecting an earthing lead to coil (-). Certainly within 100ms any flux changes and back e.m.f. will be negligible. [Faraday's law = e.m.f proportional to rate of change of flux.]

At the risk of prodding a hornet's nest, I wonder how that squares with the theory posted before you came in, that, in what is essentially now a steady-state circuit after connecting the earthing lead, 2V of the supply can magically disappear when tracing around the circuit with a voltmeter? [Kirchoff's 2nd law = the sum of voltages round a closed circuit equals zero.]

The point about back e.m.f. is quite interesting, some HT-side faults such as arcing through the rotor arm direct to earth, or open circuit HT leads, could well lead to an increase in back e.m.f. with more stress on the ignition amplifier, then causing that to fail prematurely.

The effect of the so-called suppression capacitor is also interesting. If the coil inductance is around 6mH and capacitor of 0.1uF we'd be looking at a resonant frequency in the order of 6kHz, You wouldn't want to use a massively bigger cap as the frequency will get lower.

[O mage]

adam quantrill said:

Thanks Mark, yes indeed at 6000 rpm the sparks are coming at 5ms intervals, so the coil must be pretty much fully energised and in steady state within say 10ms of connecting an earthing lead to coil (-). Certainly within 100ms any flux changes and back e.m.f. will be negligible. [Faraday's law = e.m.f proportional to rate of change of flux.]

At the risk of prodding a hornet's nest, I wonder how that squares with the theory posted before you came in, that, in what is essentially now a steady-state circuit after connecting the earthing lead, 2V of the supply can magically disappear when tracing around the circuit with a voltmeter? [Kirchoff's 2nd law = the sum of voltages round a closed circuit equals zero.]

The point about back e.m.f. is quite interesting, some HT-side faults such as arcing through the rotor arm direct to earth, or open circuit HT leads, could well lead to an increase in back e.m.f. with more stress on the ignition amplifier, then causing that to fail prematurely.

The effect of the so-called suppression capacitor is also interesting. If the coil inductance is around 6mH and capacitor of 0.1uF we'd be looking at a resonant frequency in the order of 6kHz, You wouldn't want to use a massively bigger cap as the frequency will get lower.

You could say its being inducted into the core as the magnetism and heat is created

Can we stop blaming the feed for the disappearance on all these running vehicles yet.? Since it is the coil being tested not the feed.

I doubt it somehow

[adam quantrill]

Sorry, I don't think I could say that at all. Or any circuit that I use an inductor in would be in a similar predicament, from RF front ends in mobile phones and basestations, to mains transformers, to DC-DC convertors. If you can't rely on Kirchoff's laws any more, electronic design goes up the swanee.

[O mage]

adam quantrill said:

Sorry, I don't think I could say that at all. Or any circuit that I use an inductor in would be in a similar predicament, from RF front ends in mobile phones and basestations, to mains transformers, to DC-DC convertors. If you can't rely on Kirchoff's laws any more, electronic design goes up the swanee.

All those devices heat up.!! so ok what ever is causing the drop will be heating up so if you look at all the cars that have been tested.........................................WHAT IS THE ONE THING THAT IS HEATING UP IN ALL CASES WHAT IS THE COMMON DENOMINATOR? .......THE COIL..... ITS THE COIL THAT'S DOING IT NOT THE FEED.........THE COIL IS INDUCTING THE 2 VOLTS.! ....... FFS........IT IS THE COIL YOU ARE TESTING...............F F S..............YOU STOPPED MEASURING THE FEED WHEN YOU HOOKED IT UP TO THE COIL THEN ENERGIZED IT.!!

Edited by O mage on Tuesday 16th June 23:35

Edited by O mage on Tuesday 16th June 23:47

[adam quantrill]

So what is this phenomenon, energy lost to heat? Or "inductive" energy? Please clarify!

[Penelope Stopit]

blitzracing said:

Well its been entertaining if nothing else

It has but it's getting boring now

Glad you've enjoyed some of it though

[Penelope Stopit]

O mage said:

agree but i doubt your explanation will do any good for some
I know how it works it's just that others on here definitely don't and shouldn't really be preaching if they don't understand the device being tested and what effect it has on the voltages when measuring across the two terminals.

You have misunderstood something yet mention that others don't understand

blitzracing hasn't commented that a 12 volt ignition coil primary supply should be 2 volts lower than the battery voltage when the coil negative is earthed for testing purposes and I assure you he's not going to because he knows it isn't going to happen

adam quantrill hasn't commented that a 12 volt ignition coil primary supply should be 2 volts lower than the battery voltage when the coil negative is earthed for testing purposes and I assure you he's not going to because he knows it isn't going to happen

Penelope Stopit hasn't commented that a 12 volt ignition coil primary supply should be 2 volts lower than the battery voltage when the coil negative is earthed for testing purposes and I assure you he's not going to because he knows it isn't going to happen

Remember the battery being used must be fit for purpose

When are you going to stop ?

This is getting boring now