Equipment for Measuring Turns?

how much turn of copper wire is needed for a 1 kw Permanent magnet .

Don't know if this will help.

An inductance meter should work.

For a given size of former Inductance is the function of number of turns.

Yes: search for LCR meter.

No Rakesh, Inductance is not the function of number of turns only. It is function of shape and the size of the coil also. If coil is on rectngular former, inductance will be differet than that for the same number of turns on round (cylindrical) former. Also, with same number of turns but with different dimensions of coils, you will get different inductance.

Thus, only inductance measurement will not tell you about the number of turns.

No, I think you had not red my statement with full attention, It says "for a given size of former inductance is the function of turn," As I understand from OP three is no change in former size and OP only want to detect coil to coil variation not the variation from one product to another.

Regards,

Rakesh

I could only come on CR4 after so many days, thus late in responce.

Yes, you are right on that matter. For given former, (for given size of former) inductance is function of turns. That means Hari will need a good sample as a reference.

Besides, he needs to wind the coils identically layer by layer. Any deviation in layer by layer winding will give him variation of inductance.

It's easy and at least as old as George Westinghouse (who built one), if you have access to the center. Do you?

try to assist ...if not ?????

What does your comment have to do with my question?

Try setting up a photo/optical sensor to measure turns. A small reflective or dark patch on the plastic bobbin should be all you need to make optical counting work.

How accurately do you need to know the turns count? Is this to be an in-process measurement or an after-production quality check? For an after-production quality check, perhaps a 4 wire resistance measurement would be the most appropriate solution.

Maybe you could make a standard coil with say Ns=1000 turns, apply AC voltage Vs across it, place it near the coil you want to check and measure its AC output voltage. Then turns on the coil should be Ns*V/Vs.

Hi,

Here I'm confound due to the fact that the wire is wounded over the plastic material,

Is there will be a generation of magnetic induction (As like in steel/ferrite core) ? If so, which inturn induce flux in the secondary coil (test coil) inorder to measure its O/P voltage???

Please clarify.....

Hari

Hari if you mean you need direct measurement of turns, you can simply convert an inductance meter in turn teller by calibrating its electronic card.

Nothing can measure better then this.

I'm afraid that's incorrect. L will only count turns if everything else is precisely known. Faraday's Law will count turns quite accurately, quickly, and cheaply.

Had you red the OP.How many formers is he talking about?If he is talking about one former doesn't it means everything else is precisely know? I think our replies should be in the context of what original question is?

Beside this, before calling others incorrect we should put some thoughts,

BTW if coil is wound on solid plastic former as he mentioned it. How are you going to get the repeatability of magnetic flux that is going to pass in search coil?

Regards.

Yep, he said "process". You don't have a "process' for one off items.

I didn't call you incorrect; I said your answer was incorrect. It is. In a "process" you can't control the physical dimensions well enough to get a precise geometry, thus L will vary. You can control the dB/dt more than well enough.

Does this look like an R-L bridge?

Correct,

The company were I had worked this is how the winders worked, giving a consistant result.

To the OP, Does it have any feed back on the winder?

There are always method to produce right thing at right place and that applies to winding machines and process also.

But that doesn't mean there is no need to check coils for there Consistency.think of a case where you are using thin enameled wire and coil having turn to turn or layer to layer to layer short.

I think OP is smart enough to fix a turn counter at right place. there must some reason for his question.

hello rakesh_semwal

Thats true, just relaying how some actual coil winding machine are, let the OP decide.

I like to think there are a number of ways to handle it, the best thing to do may not be the right thing to do. (And the right thing may not be the best, but is acceptable)

Has been my experience, not to assume. So I just put it out there, use it or ignore it.

p911

Excellent point. Good quality control should include more than one metric.

IMHO, a turn counter would be a good first level manufacturing criteria. Secondary tests for inductance and resistance would be prudent QC steps to detect any process defects and verify the end product is within desired specifications. The L-R testing can usually be done in-line so it should not significantly limit the production rate.

I note that Haricool has not answered. This is not rocket science. I have measured perhaps thousands of coils for number of turns. It is quite simple (as Guest pointed out, sort of) if you have access to the center. So, Haricool, do you?

You have two choices. First, you can put a temporary core through the coil and measure the voltage induced by a known number of turns wound on an adjacent coil. The second metod is to put a cunductor through the coil and run a known current through the conductor. This will be a Rogowski configuration-no core required.

Rather late to be posting... but i have used the Tinsley turns tester for a long time, for measuring turns of an already wound coil. My company used to make several thousand coils for contactors, and, while the machines were Swiss and very accurate, it was still deemed essential to (a) count the number of turns and (b) check if there are any shorted turns. In an AC contactor coil, any shorted turns mean disaster. Please check this out ... tinsley

In India, there are some good ones which may do also...one here,

vasavi