ignition transformer wiring

[cdd]

Which of these two statements are true- When wiring the secondary of a

15kv (.25A) transformer you should ground one side of the centre tapped transformer to earth if it is not used, as the ignition assembly only has one electrode and a grounding terminal to produce it's arc across. Or should it be connected to nothing? What effect is earthing one side of the secondary having on the transformer?

Yes ideally the transformer would have a single HT lead coming from it and then this wouldn't be a issue but I am referring to a series of heaters that were built this way..

[Stormin Mormon]

Electricity travels in a complete circuit. The secondary on some transformers is connected to the metal case of the transformers. (think Chrsysler igniton coils, from the sixties and seventies.)

In the situation you describe, I'd not worry about earth ground. I'd want to make the complete circuit for the electricity. So, one "hot" wire to one electrode, and a ground wire from the coil to the other electrode.

[-zero]

Sounds like it's a mid-point grounded transformer. Do you have a model#/make?

Which ever way they were built, it falls on the manufacturer's shoulders.

-zero

[Old Grunpy]

cdd hi no joke O M transformers? first you must know if your ignition system is design to operate at 7.5kv are is design to operate on 15kv in my opinion your transformer is not center tap, what you assuming to be center tap I believe that is copper shield which it should be grounded that is to limit noise from arcing of electrodes. check if you have continuity from the tap to the output of high voltage terminal it should in K ohms. also check if continuity is present to the case of transformer if is shield it will have high resistance in mega. ohms. to the case and high voltage terminals. Tony

[cdd]

If I take the earth on the primary side of the transformer then with my fluke meter take a restance test between that earth and one of the secondary windings I get a k ohm reading -the same with the other secondary -it even say's on this danfoss transformer that it has it's centertap earthed - If I wire the transformer up I only have too put one of the secondary wires near earth and it arcs as well confirming this is true,my question is what is happening to the transformer when then center of the sec is earthed as well as one of the secondary outputs as well it-will this overload the transformer?

[Mark]

if the secondary is really center tapped and grounded then you do not need to and should not ground either of the other two leads,,, if you do ground one of the end leads, you will be putting a short across 1/2 of the secondary and that is not good.

Mark

[cdd]

..

That is exactly what i have been getting at - but what is it doing to the transformer? I have worked on many of these units and it's always the primary that blows-is the transformer being over loaded due to the way they have wired them( I have been replacing them with non centre tapped transformers)

[Mark]

m...

if you short 1/2 of the secondary, the transformer will run hotter than it needs to ...

an arc is sorta like a short but adding another short on the secondary can only make the unit run hotter which is not a good thing for long life. Mark

[new jersey]

if you short 1/2 of the secondary, the transformer will run hotter than it needs to ...

YOU MEAN IT WILL BURN UP "RIGHT" ?

an arc is sorta like a short but adding another short on the secondary can only make the unit run hotter which is not a good thing for long life. Mark