Multi Stranded Wire

[abbarue]

Maybe this question has been asked before:
Is there a problem using Multistrand wire like speaker wire(not litz wire) for winding inductors, or transformers?
Would it work for building a Tesla coil for example?
Or for winding bifilar coils, seeing speaker wire is already bifiler off the roll.
The reason I ask is, I have lots of speaker wire on hand,
and it is very easy to get at the local stores.
But solid single strand magnet wire is only available through online orders.

 

[KeepItSimpleStupid]

1. Winding density would be much smaller
2. Insulation breakdown would be much lower.
3. Friction losses would occur at each strand.
4. Magnetic losses would be higher.

A tesla coil requires a lot of turns. It won't be possible with all of that insulation.

 

[Gauthamvg]

tesla coil primary core needs 'loosely coupled heavy insulated wire' of size 18 AWG. As for as i know no multi stranded wire is insulated with enamel coating, like the single stranded wire,. as KISS said, the magnetic loss would be higher, Never use multi strand wire for these type of experiments, i have blown up fuses in similar case ,

 

[Sceadwian]

The only advantage that common multistrand wire confers is flexibility, which is of no use in the case of an inductor or transformer except for a perceived convenience when winding.

 

[Mosaic]

1. Winding density would be much smaller
2. Insulation breakdown would be much lower.
3. Friction losses would occur at each strand.
4. Magnetic losses would be higher.

A tesla coil requires a lot of turns. It won't be possible with all of that insulation.

What is 'friction' losses?

 

[KeepItSimpleStupid]

The 60 Hz vibrations cause he strands to vibrate against each other (friction). This creates additional heat.

 

[Dean Huster]

The only advantage that common multistrand wire confers is flexibility,

And with this flexibility, we usually think of things like test leads, power cords and such or wire that we can easily pull through conduit. But it's this flexibility that also keeps it from easily breaking under vibration, making it the ideal wiring for automotive, marine, avionics, etc. Another disadvantage of stranded wire is using it for oint-to-point circuit wiring. It's miserable to poke through lugs and even more miserable to desolder. Tinning the ends of stranded wire with solder or double-roll crimping a lug to the end is the only way to deal with it when connecting it to terminal screw strips.

 

[KeepItSimpleStupid]

Terminal strips are OLD TECHNOLOGY. DIN terminals or terminals with "wire protectors" work fine. It's preferrable to use "wire ferrules" for stranded wire.

Even stranded wire doesn't hold up sometimes. I had pop-up headlamps and the wire didn't survive the flexing. I replaced it with test probe wire.

You can buy wire with various stranding say 7/32 or 14/40 (made up). 7/32 stands for 7 strands of 32 AWG wire. the lower stranding works great for point to point wiring.

 

[Dean Huster]

.... the lower stranding works great for point to point wiring.

I've torn apart enough old TVs, radios and other items during the last 40 years to know that stranded wire used for hook-up wire in point-to-point wiring is straight from the Devil himself, the stuff being the surest way to ruin tube sockets and terminal strips, the very thing you were trying to save back in "the old days". And right along with that, the age-old tenet of doing multiple wraps of any wire around a terminal so that you can have a "good mechanical connection before soldering" is a major bunch of crap. If a high-end, high-reliability builder like Tektronix does well with a simple poke through a terminal (NO WRAP AT ALL) and solder method of construction, then what's the point of doing anything else?

 

[Reloadron]

If a high-end, high-reliability builder like Tektronix does well with a simple poke through a terminal (NO WRAP AT ALL) and solder method of construction, then what's the point of doing anything else?

Why of course to make it more difficult to unsolder it.

Ron

 

[KeepItSimpleStupid]

I do remember trying to unsolder, say a transformer connection from a tube socket. Not any fun at all.

 

[jpanhalt]

I have used multi-stranded welding/battery cable (the very flexible, high count kind) to rewind the secondary of a microwave transformer to make a spot welder. I can't image winding the same coil with 4 gauge solid copper wire. It worked fine. At some point, practicality out weights theory.

John

 

[Sceadwian]

Only for the application jpan, of which transformer winding in the extremes of re winding a MOT as a spot welder is definitely one of them.

 

[jpanhalt]

As they say in Kentucky, different horses for different races.

John

 

[Sceadwian]

Well said John.

 

[Reloadron]

As they say in Kentucky, different horses for different races.

John

But, but, but.... You are in the Cleve and not Kentucky.

Ron

 

[abbarue]

Well thanks for the info! Now does anyone know where I can get some
18 AWG solid wire with the thicker insulation on it?
Not the magnet wire used for transformers, I can find all kinds of that.
It needs a thicker insulation to withstand higher voltages, without braking down.

 

[Reloadron]

Insulation breakdown is based on a combination of things, including insulation material. What working voltage do you want?

Ron

 

[mechatronix]

Hi abbarue,
In our shop we tried speaker wire once for widing a coil, but it didn't work well - the insulations is too stiff compared to other wire.....be careful using speaker wire for high voltage - I don't think it is rated for more than 50V or so. You need MTW

 

[mechatronix]

Hi abbarue, One more thing.... on MTW wire...and other wire

You asked about 18 Gage wire. If you want just any wire and single colors, any hardware store will do, but if you want quality, you need better than Ace or Radio Shack. Our shop does a good bit of custom machine building and we buy all of our wire online from a company out of Michigan. It's called Wire Barn Wire Barn and the main wire we buy is called Machine Tool Wire (MTW). You need MTW for high voltage. MTW withstands 600V without breaking down. If you don't need AC type voltages, we buy their GXL or TXL wire (it's automotive ONLY type of wire - lower voltages). Anyway, their wire is real good but you have to buy packs (multiple sets of a given length - we buy a lot of 8 packs and it does us well). If you just want a single piece of wire, go somewhere else, but they are great if you want a lot of wire in different colors and gages it's great.