# do high current, high inductance inductors even exist (say 5A, 5mH) - Page 2

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Re: do high current, high inductance inductors even exist (say 5A, 5mH)

wroth:

A two-terminal black box that had the characteristics of a large, high
current, inductor would be a neat design goal.  A high frequency DC-DC converter
to charge energy storage caps from the input current and some active circuitry
to return that energy to the input at the appropriate, inductor like, time might
do the job.

Jim

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

Here's a 500mH inductor:
http://www.falstad.com/circuit/ex-gyrator.html

You can even edit the circuit, click component to
select, right-click to edit.

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)

Re: do high current, high inductance inductors even exist (say 5A,5mH)

and how, pray tell, is that useful at 5A?

Cheers
Terry

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

There are power op-amps on the market that can handle this sort of current
easily, or a power output stage could be added to a cheaper op-amp, so a
gyrator solution could be used. Depending on the frequencies involved,
many quite cheap audio amplifier IC's, might be 'good enough' to work for
this sort of application.

Best Wishes

Re: do high current, high inductance inductors even exist (say 5A,5mH)

I'll buy the power opamp argument (eg LM12). I dont have a java plugin
running, so cant see the schematic. but what are the series resistors
for 5mH? how many volts will they require at 5A? what will the losses be?

for the Antoniou inductance simulator, L = CR^2 (all identical R's).

For L = 10mH, you are going to need one hell of a large (bipolar) C for
even a reasonably small R. I'm not going to analyse the thing in terms
of available opamp swing etc (cant do that until know requirements of
"inductor") but odds-on you're pushing shit uphill with a pointy stick
here :)

It would actually be an interesting analysis to do - at what point does
an inductor "win" over an opamp. And just what do we mean by "win" -
smaller? cheaper? lighter? less lossy?

Cheers
Terry

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

It will make some pretty colours, sound and even smoke too - get the kids
off the PeeCee for a few minutes L.O.L.!

Re: do high current, high inductance inductors even exist (say 5A,5mH)

Very true.

I once made something useful using 24 Z80 microprocessors (circa 1987) -
I glued little eyes, wings and tails on them, and made a mobile.

Cheers
Terry

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

It would look like a transformer.  In fact, I might approach this problem by
measuring the inductance of individual windings of various transformers,
always choosing windings that can carry the rated current or more.

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

"mc"

** Then you would be making a major blunder.

Transformer ( 50/60 Hz types) windings are not designed to be used as power
inductors, rather they have very high intrinsic inductance values with low
current passing capacity  -  unless the current flow is induced by a load on
another winding.

OTOH,  an iron cored inductor is wound and designed to have a particular
inductance value and pass a particular maximum current value before core
saturation occurs. This is normally achieved by introducing a small air gap
between the E and I laminations which are stacked together and NOT
interleaved.

Wound steel cores ( toroidal etc) need to be cut with a saw to create such
air gaps for use as power inductors.

.........    Phil

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

http://www.hammondmfg.com/153.htm

RL

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

Check web sites that cater to loudspeaker builders:

http://www.madisound.com/cgi-bin/index.cgi

see "inductors"

http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID31%0

http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID31%4

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

"Arny Krueger"

**  Care to nominate any inductor from those URLs that comes nears a 10mH
and 10 amp continuous spec  ??

.........   Phil

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID19%7#15gauge

Part number 255-448.   14 gauge wire is rated for 15 amps as
AC cable, so 15 guage should only experience moderate
heating with 10 amps.  Being air core, it should also be
quite linear.

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

Arny ! SHUT UP !

It's 1.2 Ohms. That's 120W of dissipation ( before it gets hot ) !

Pls go back to discussing soundcards - you're not an EE.

You *have* to use magnetic materials for this kind of thing. Air cored is
no good.

Graham

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

Lack of minimal adult intrapersonal skills noted.

Whoops. Point well taken.

In fact I am fully formally educated as one, but sometimes
my attention to detail is a little slack. Obviously Graham,
you have yet to make your first mistake.

Graham to quote a man who is very impressed with himself,
you're obviously not an EE. An EE would know that this is
just a problem of scale. Air cored is fine, just large and
expensive. ;-)

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

That's a particularly stupid comment.

I doubt you could find an air cored inducutor that fulfilled the requirement
without it being 'obese' by normal standards.

Graham

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

Yes, because it quotes you.

Whatever that means.

Come on Graham we both know that the OP figured out that his
requirement overstated the need by a factor of a thousand.

ASe you running a surplus of bile to work off, or what?

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

Arny Krueger wrote:

How do you think I earn my living ?

Graham

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

Electronic design, which does not necessarily require an EE.

For example, a friend of mine who is both an EE and earns
his living doing circuit design tells me that virtually none
of the chief engineers of high end audio firms that he's
made the acquaintance of (and that would be goodly number)
has anything like the credentials of an EE.

Re: do high current, high inductance inductors even exist (say 5A, 5mH)

"Arny Krueger"

** You are all confused Arny -  as usual.

The abbreviation " EE  " describes  either an  "Electrical Engineering"
degree ( aka a BE  )  OR   a person who works as an electrical/electronic
engineer. To work as and be called an " EE " in electronics does not require
one to hold a BE degree.

In any case, one either knows or has a good understanding of some technical
matter  -  or one does not.

Worthless scraps of paper have no relevance.

........   Phil