Inductor Basics: 2 Windings or More?

In summary: I was referring to inductor saturation. All inductors have a saturation current Isat, and if you exceed that Isat, the inductance value diminishes. Look at the B-H curve to see how there is a saturation flux density where the B versus H curve starts to bend over:When the H field reaches a saturation value, the B value stops climbing linearly, so the effective inductance value goes down. This is important in power electronics, and also in communication transformer design. When you mentioned that they were doubling up the two windings on the inductor to get 4x the inductance, that doubles the Amp*turns for the inductor. If the inductor was meant to be a transformer, for example,
  • #1
sandy.bridge
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The other day one of our power labs we were using rather large inductors; that is, approximately 10"x4" in the shape of a doughnut. There were 4 connections into the inductor. We connected a wire from one to the other, and then used the other two connections as any other inductor. Does that merely mean there was two windings, or am I missing something here?
 
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  • #2
sandy.bridge said:
The other day one of our power labs we were using rather large inductors; that is, approximately 10"x4" in the shape of a doughnut. There were 4 connections into the inductor. We connected a wire from one to the other, and then used the other two connections as any other inductor. Does that merely mean there was two windings, or am I missing something here?

Sounds like it's a transformer or maybe being used for a common-mode choke?
 
  • #3
Decided to go in and ask what it was we were using. It was indeed two inductors in one, and we were essentially putting them both in series to get a greater inductance.
 
  • #4
sandy.bridge said:
Decided to go in and ask what it was we were using. It was indeed two inductors in one, and we were essentially putting them both in series to get a greater inductance.

Interesting. Thanks for the info.

Quiz Question -- what parameter do you need to check when doing something like that? There can be a problem when you double the amp-turns on an inductor...
 
  • #5
We checked both the resistance and the inductance.
 
  • #6
sandy.bridge said:
We checked both the resistance and the inductance.

What do you mean by "you checked the inductance"...? :smile:
 
  • #7
By checked I meant measured!
 
  • #8
But that doesn't address my Quiz Question (which is optional of course). When you double up the amp-turns on an inductor, what should you be concerned about? What datasheet spec should you check? Or what experiment should you run to be sure you still have an inductor?
 
  • #9
If the meter is reading an inductance, would that not indicate that it is indeed a inductor? I know that wires have some inductance, but not as much as what we measured. I'm not quite following, but I'd like to know for future reference.
 
  • #10
sandy.bridge said:
If the meter is reading an inductance, would that not indicate that it is indeed a inductor? I know that wires have some inductance, but not as much as what we measured. I'm not quite following, but I'd like to know for future reference.

I was referring to inductor saturation. All inductors have a saturation current Isat, and if you exceed that Isat, the inductance value diminishes. Look at the B-H curve to see how there is a saturation flux density where the B versus H curve starts to bend over:

http://en.wikipedia.org/wiki/Saturation_(magnetic )

When the H field reaches a saturation value, the B value stops climbing linearly, so the effective inductance value goes down.

This is important in power electronics, and also in communication transformer design. When you mentioned that they were doubling up the two windings on the inductor to get 4x the inductance, that doubles the Amp*turns for the inductor. If the inductor was meant to be a transformer, for example, then using it in this way might exceed the Isat rating for the core. Just something to think about when using transformers and inductors...
 
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FAQ: Inductor Basics: 2 Windings or More?

What is an inductor?

An inductor is an electronic component that stores energy in the form of a magnetic field. It is typically made of a coil of wire and is used in a variety of electronic circuits to control the flow of current.

How does an inductor work?

When current flows through an inductor, it creates a magnetic field around the coil. This magnetic field then stores energy, which can be released when the current flow is interrupted. This property of inductors is what makes them useful in various electronic applications.

What is the difference between 2 windings and more in an inductor?

An inductor with 2 windings, also known as a single-winding inductor, has one coil of wire. In contrast, an inductor with more than 2 windings has multiple coils of wire. The main difference between the two is the amount of inductance they can provide, with multiple-winding inductors having a higher inductance value.

How do you calculate the inductance of an inductor with multiple windings?

To calculate the inductance of an inductor with multiple windings, you can use the formula L = μ * N^2 * A / l, where L is the inductance in henries, μ is the permeability of the core material, N is the number of turns, A is the cross-sectional area of the core, and l is the length of the core. It is important to note that this formula may vary depending on the specific design and construction of the inductor.

What are the applications of inductors with multiple windings?

Inductors with multiple windings are commonly used in radio frequency circuits, power supplies, and signal processing circuits. They can also be found in various electronic devices such as computers, televisions, and mobile phones. The increased inductance provided by multiple windings allows for better control of current flow and improved performance in these applications.

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