Infinity crossover coil value

Plugging in the values, I seem to get slightly higher values of L1. but not much. A crossover cannot be tested by itself. The drivers also play into the crossover, also making poles and things. I would try some real time values and listening test. the value should be between .3 and .5 mh. If you could measure the R, unwind the coil, and measure R, that might tell the extent of the damage.

greg

catalogs.infocommiq.com/AVCAT/CTL1857/index.cfm?mlc_id=1857&NOTRACK=1&pin_id=2345&prodID=315911

People still use the term "ring out" to test wiring. I did not start this thread to be argumentative. Although any thread with Arny in it seems to end up this way. Arny as the only one who seemed to not know about what a coil ring test was and to make a bone about it.

Sencore is well known in the service industry for specialized service test equipment. Anybody can google it or go to their web site for further information.

What i originally said was:

"I tried to read the coil on my sencore, and it measures about .3 MH. It won't pass any ring test (air core) so i know turns are shorted and this value is suspect. Any clue on the value of this coil?"

So the words Sencore, coil, ring, test are all there. Just maybe not in the order that Arny would like.

Why is it that all anybody wants to discuss is ring tests rather than suitable coil replacement values?

When i get some time, i'll have to find the equations and try to solve for the inductor value and get the closest standard value. That's what this thread was all about.

Bob

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To test coils and flyback, there is a common test. There is also a modern device, really simple. A pulse generator connected to a scope. That is a problem for me in testing coils. i don't usually have anything set up to make sure the coils are not shorted. A driver would also have problems with only a turn or two shorted. I saw nothing wrong with the way Bob presented his case.

greg

What do Phildo and george have to do with this thread? And this is NOT posted to AAPLS. Get your groups straight Arny.

And unlike those you mention, i actually fix things.

Simple technical question. Who has the answer? I guess you don't............

Bob

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The link i provided was found with a quick search. I am guessing its that topology. Some of the information seems to be conflicting.

What do you mean by measure R with the coil wound and unwound?

Bob

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Is he ?

I thought he was smarter than that but I don't see his posts here since Supernews filter his posts.

Graham

Supernews filter my posts? Interesting. Check google groups for a recap.

Is all about a crossover coil value question if you would like to help Graham.

If you believe Arny, i got some swamp land.........

;)

Bob

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As usual Bob, you're being deceptive. I wasn't talking about the search string "coil ring sencore".

If I didn't know anything about this type of equipment, how would I know that Sencore would be a relevant word to use for searching google?

One other helpful tip for you Bob. I've repaired a lot of computers, radars, and audio equipment, both pro and consumer. But, I've never ever fixed a TV other than checking the tubes and replacing the ones that checked bad.

Exactly.

One finds a lot of Sencore equipment in TV repair shops. I last spent any time at all in a TV repair shop before I graduated from high school.

If I sat down and thought about it for a while, I'd figure out that Sencore did have a flyback transformer tester in their product line, and that it should have a shorted turn detector in it.

Agreed. It also has meaning in the context of live sound which is yet another area where Bob likes to pretend that I'm an idiot.

Unwinding removes the short. You may actually see where the short is, ir may be welded together.

grge

It also determines the R total shorted, and unshorted.

greg

What good is R shorted or unshorted? I unwrapped the coil. It measured on the FLuke about .2 either way. It was burnt down. to the bottom layer(5 layers or so). And the coils bobbin (plastic) was melted and deformed) Even with only one layer showing, it still flunked the ring test.

Bob

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I guess the short could be complex. I was trying to determine what persentage of the wire was shorted. You have to wonder, what exactly is going on here.

I would not trust the amp or the tweeter. I would want to insert a fuse next time.

greg

Nothing strange here, a 24 dB L-R filter can only be claimed implemented if the acoustic output from the units actually have the proper acoustic slopes when combined with the filter.

Regards

Peter Larsen

Surely the customer has stereo in the car, so one avenue would be to ask for the other cross-over as a source of comparison.

OK. You know the target response, and implicitly it is the tweeter cross-over slope this is about. Tweeter response is reasonably easy to measure, so if you replace the coil with a guesstimate coil it is possible to determine in what way the replacement coil is incorrect.

CALSOD comes with a lil' util called inductor.exe, it is quite possibly not the only software on the planet for calculating inductors, and its existence suggests that the4 coil geometry can get you a close estimate of the inductance of the coil.

It would be good design practice to design a cross-over that fits the units so that the number of components can be reduced.

You know the coil geometry, you know the wire diameter, it should be possible to get an estimate of the lenght of wire in the coil. That should make it possible to calculate a probable value for its resistance. Determining the actual resistance and comparing may provide correction data that can be used to convert the measured impedance of the coil to what it should have been.

Regards

Peter Larsen

Passive network transfer function, as I understand it when loaded with actual loudspeaker load, is available in the .pdf you linked to. A few trial and error substitions should lead to the correct coil value. You really have to verify that the units are OK anyway.

Regards

Peter Larsen

Agreed. Furthermore, the crossover drives a reactive load, not a resistive one.

So, the crossover is unlikely to have an 18 dB/octave response that its electrical configuration suggests. I suspect that it drives the tweeter just above its resonance, where the tweeter is more like a capactive load. The

This nets out to more like a 12 dB/octave high pass filter, which would combine with the 12 dB/octave high pass acoustic characteristic of the tweeter to provide a 24 dB/octave filter.

bob, are you sure the schematic you drew at the first post is correct? i ask because i have found that tweeters usully have a series capacitor rather then an inductor.

can you load the remaining portion of the crossover in such a way as to determine the crossover frequency by sweeping with a signal generator?

nevermind... i see it now.

how come those bozos could give you the thiele small peramiters but not include a simple schematic?