In article , NONONOmisc07
@bigfoot.com says...

Oil furance ignition transformer. Proper resistance for primary.

Is it possible that a winding with only 4 ohms DC resistance would
have 52 ohms impedance at 60 Hertz**?

I have an ignition transformer for an oil furnace burner.

It's designed to make a continuous spark to ignite the atomized fuel
oil sprayed into the firebox. It runs on 120 VAC. And the
secondary is meant to provide a voltage that will jump across a
specified 1/8" gap, but probably will jump a 1/4" gap. I see that the
transformer secondary is rated at 10,000 volts.

Disconnected and measured with an ohmmeter it shows 20,000 ohms in the
secondary, and 4 ohms in the primary!!

Is that possible? Esp. the primary.

I don't know how to measure impedance at 60 Hertz.

The transformer primary uses 2.2A at 120 volts, according to its label

(The current in the secondary is 23mA. The transformer is a lot like
this one:
https://www.grainger.com/product/ALL...sformer-23M552
)

E=IR, R = E/I = 120/2.2 = a little over 52 ohms, right?

That would make the impedance at 60** Hertz about 52 ohms, right?

Is it possible that a winding with only 4 ohms DC resistance would
have 52 ohms impedance at 60cps**?

Or is the transformer bad?

Or what am I doing wrong?

The transformer seems to fail when it's hot, but it wasn't hot when I
measured the resistance of the windings.


**Or maybe 15 to 30KHz. Some replacement transformers specify that,
but I think it's only for quite modern furnaces. I don't think my old
furnace would have that. It has a circuit board with about 30 parts,
but I don't know what parts to look for that would be an oscillator.

Thanks.

SOunds ok to me.. The wire is of small gage so you would expect some DCR
readings of significant value, especially on the secondary side.
Jamie