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large inductance measurements of Leybold coils (from 1uH up to 1 kH)

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LAN_403

Physikfan

Sat Jan 28 2017, 03:37PM

Registered Member #60240 Joined: Mon May 16 2016, 07:01PM
Location:
Posts: 304

I would like to post some data of measurements of large inductances,
but I have no idea how to present the data in a format similar to an exel sheet.

Please, could somebody give me some hints?

Regards

Physikfan

Sulaiman

Sat Jan 28 2017, 05:57PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

just a note,
often the easiest way to measure large inductances is to;

pass a known dc current through the inductor,
'catch' the flyback with a capacitor via a suitable diode
measure voltage across capacitor, .... calculate

based on E = 0.5 x L x I x I for inductor, E = 0.5 x C x V x V for a capacitor.

Bjørn

Sat Jan 28 2017, 11:07PM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

Watch your fingers when doing this. It is easy to get too relaxed when working with low voltages, a large inductor can be extremely unpleasant when it suddenly releases its stored energy.

Dr. Slack

Sun Jan 29 2017, 05:02AM

Registered Member #72 Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659

do you mean, like this?

sample   inductance    seriesR
 01       103.2H        1.3ohm
 02        18.7kH      12.3ohm

which is cut'n'paste a text file of fixed width columns between code tags, the <> button
Or you could attach the text file itself, or an excel file that's been printed to pdf
Attach a png screenshot of a excel file being displayed works as well.

Physikfan

Sun Jan 29 2017, 06:28PM

Registered Member #60240 Joined: Mon May 16 2016, 07:01PM
Location:
Posts: 304

Hi Dr. Slack, BjÃ¸rn, Patrick and Sulaiman

The data should have the format which I will present in my next posting.

To create this jpg I had to copy the table into the program paint.
But doing so it is extremely difficult to correct even one number only.

Are there more simple procedures possible?

Regards

Physikfan

Physikfan

Sun Jan 29 2017, 08:32PM

Registered Member #60240 Joined: Mon May 16 2016, 07:01PM
Location:
Posts: 304

Large coils have something fascinating:

1. The opening spark, which when switched off, reflects the magnetic energy stored in the coil.
2. The slow current increase at power up, which may take up to a few seconds.
3. With a capacitor of 50 Î¼F, a free attenuated resonant circuit of about 1 Hz can be realized.

However, reliable values â€‹â€‹for the inductance L in large coils can not be determined so easily.

I would therefore like to try to animate members of this forum, to present their own measurements on large inductors.
They should also explain their methods of measuring L and also mention any problems.

For my part, I would like to present measurements on relatively world wide easily accessible Leybold coils.

Measurements of the inductances of the coils of Leybold with LCR meter Agilent 4236B, 1 V amplitude, measuring frequency 120 Hz.

Overview of Leybold Coils
Cat.-No.,
562 19 coil with 5 turns, load 500 A, wire thickness 8.0 mm Ã˜
562 18 coil with 50 turns, permanent load 10 A, wire thickness 2.0 mm Ã˜
562 13 Coil with 250 turns, permanent load 5 A, wire thickness 1.5 mm Ã˜
562 14 Coil with 500 turns, permanent load 2.5 A, wire thickness 1.0 mm Ã˜
562 15 Coil with 1 000 turns, permanent load 1,25 A, wire thickness 0,7 mm Ã˜
562 16 Coil with 10 000 turns, permanent load 0,1 A, wire thickness 0,2 mm Ã˜
562 17 Coil with 23 000 turns, permanent load 0,02 A, wire thickness 0,1mm Ã˜

TableLeyboldAgilent

Not all measurements showed meaningful results, note the unfilled places in the matrix.

Sulaiman

Sun Jan 29 2017, 09:37PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

given the low 2.pi.F.L/R of these inductors
and the non-linearity of the iron core B vs H
and frequency dependence of the core loss factor
specifying and/or parameterizing inductors is non-trivial.

Usually it is best to test in its intended circuit at its intended rating,
or, to standardize results, you could provide each of us with a 4236B

Patrick

Sun Jan 29 2017, 09:54PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Dont kill yourself. please.

Physikfan

Mon Jan 30 2017, 10:01AM

Registered Member #60240 Joined: Mon May 16 2016, 07:01PM
Location:
Posts: 304

Examples for the investigated Leybold coils:

L5trim

Coil with 5 turns

L50trim

Coil with 50 turns

L10000trim

Coil with 10000 turns

L23000trim

Coil with 23000 turns

Physikfan

Wed Feb 01 2017, 09:05AM

Registered Member #60240 Joined: Mon May 16 2016, 07:01PM
Location:
Posts: 304

New measurements of the inductances of the Leybold coils with LCR meter GW Instek LCR 817, 1 V amplitude, measuring frequencies 12 Hz and 120 Hz.
Note the large available range of the inductances (from about 1 uH to about 1kH)!

TableLeyboldInstek187

To compare these new measurements (Instek LCR) with the old measurements (Agilent 4236B), the old measurements at the measuring frequency of 120 Hz are shown again.

I am looking forward to your comments!

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