Home wound inductors.

[Big_Bill]

Can one use plastic insulated copper wire for making inductors as an alternative to the traditional enamaled copper wire? If so, what (if any) are the drawbacks?

Big_Bill.

[Moondog55]

I asked this very same question myself just last week.
The answer was SIZE

The insulation on house wiring means the inductors get big quick

[Big_Bill]

Originally posted by Moondog55
I asked this very same question myself just last week.
The answer was SIZE

The insulation on house wiring means the inductors get big quick

So size is the ONLY drawback?

[CLS]

The thick plastic insulation tends to be too flexible, so the winding can not maintain stable, or at least very difficult.

And then the much thicker insulation means outer layers of winding get bigger very fast, thus you need very long wire to get the proper number of turns -- that means high DCR.

I'm curious, though, is there any benefit? Is PVC sheilded wire cheaper than enamelled?

[BlueWizard]

The function of a coil is related to the interaction of the magnetic flux between the windings. That means, for the coil to work best, the wires need to be as close together as possible. They have to be tightly coupled.

The insulation means the wires are that much farther apart and that much less tightly couple. I would suspect it would take much more wire to achieve a specific inductance value.

Also, if you use lamp cord, it is made up of very small strands of wire that are twisted. That seriously confuses thing. Now you have coils within coils, and what the outcome will be is anyone's guess. Is the twist of wire acting counter to the winding of the coil, or is it acting in cooperation with the winding of the wire in the coil?

To make standard solid wire coils, tons of information is available to at least get you very close. But with stranded insulated wire, you are on your own in trying to figure out what it is going to take to reach a specific value of coil. Plus, when the coil is done, I wouldn't expect it to work as well as a tightly coupled coil.

Overall, it is a waste of time, effort, and materials for a coil that really, probably, isn't going to work all that well.

Just one man's opinion.

Steve/bluewizard

[badman]

What he said

[Big_Bill]

Originally posted by CLS
The thick plastic insulation tends to be too flexible, so the winding can not maintain stable, or at least very difficult.

And then the much thicker insulation means outer layers of winding get bigger very fast, thus you need very long wire to get the proper number of turns -- that means high DCR.

I'm curious, though, is there any benefit? Is PVC sheilded wire cheaper than enamelled?

I found 2000 feet of PVC insulated 18 awg solid copper single conductor wire for 40 dollars SHIPPED! So I'm torn between the idea of cheap larger coils or smaller more expensive coils.

[Big_Bill]

Originally posted by BlueWizard
The function of a coil is related to the interaction of the magnetic flux between the windings. That means, for the coil to work best, the wires need to be as close together as possible. They have to be tightly coupled.

The insulation means the wires are that much farther apart and that much less tightly couple. I would suspect it would take much more wire to achieve a specific inductance value.

Also, if you use lamp cord, it is made up of very small strands of wire that are twisted. That seriously confuses thing. Now you have coils within coils, and what the outcome will be is anyone's guess. Is the twist of wire acting counter to the winding of the coil, or is it acting in cooperation with the winding of the wire in the coil?

To make standard solid wire coils, tons of information is available to at least get you very close. But with stranded insulated wire, you are on your own in trying to figure out what it is going to take to reach a specific value of coil. Plus, when the coil is done, I wouldn't expect it to work as well as a tightly coupled coil.

Overall, it is a waste of time, effort, and materials for a coil that really, probably, isn't going to work all that well.

Just one man's opinion.

Steve/bluewizard

Thanks BlueWizard and Badman!

This is the information I need to make my choice.

[Moondog55]

In the long run it is cheaper and better to go with good ingredients.
I've gone the cheaper route and it ended up costing me time and wasted effort ( although I did learn a lot in the process ) learn form my mistakes.
If you are going to buy wire buy the biggest gauge you can afford, find an electric motor rewinder in your area they may be able to sell you some by the kilo, it is far to expensive to pay Tandy retail prices and shipping

[BlueWizard]

Just a little side note stating the obvious, but I want to make sure it gets said.

The apparently bare wire that is used to wind coils, is not bare wire at all, it is still insulated, it is just insulated with a thin layer of enamel.

Most building supply stores sell enamel insulated wire in heavy gauges, but they also sell bare wire in those same gauges. Make sure you get the right one.

Also, and again stating the obvious, you will sometimes see coil winding wire listed as 'magnet' wire. This wire, to the best of my knowledge is neither magnet or magnetic. I'm not sure where that name came from, but it is just enamel coated wire for winding coils.

So, my central point is that coil winding wire is still insulated, it is just insulated with a thin coating of enamel.

Steve/bluewizard