Folks:

I need some help. I have a toroid inductor that is very small, is 6 henry, and is 100 ohms. I need to get one for a repair I am doing. Does anybody know if someone supplies these in single quantities?

Aram

 

Hello,

Are you sure it is 6 H and not 6 mH?
A 6 H coil would be much larger as in the photo.

Greetings,
Bertus

 

I am very sure... And i didn't believe myself, but I found another in the circuit that was identical to the schematics and yes it is 6h.

Thanks

 

What is the physical size? If it is as small as it looks there really isn't any way it can be 6H, inductors are more sensitive to physical size than capacitors. It couldn't take much current either, since the wire is going to be tiny (for the number of windings), but that would explain the 100Ω.

6 millihenry is huge in the world of inductors.

 

even 6mh is a huge number for an inductor, let alone 6h.

 

Okay Bill:

Let me tell you what I know... This came out of an Acoustic 370 bass amplifier, which is circa 30 years ago. (6 band equlaizer section). I used my sencore to verify other inductors in the circuit to see if it matched the schematic, and all the values were right on relative to the schematic. The schematic says that the one I need is also 6H. There is an identical one in the circuit as well. I ran this past a fellow engineer and we are convinced it is 6h. This particular one is blown open. This one is in the is on the 50hz slider.

I can't really repair it because I think the wire is like 35awg or somwhere like that. To try to make one at 100 ohms, would be tough, and laborous.

The size is 3/4" by 3/4" radial leaded, and has 007 stamped on the back, and was dipped in some sort of urethane material.

Does this help?

Aram

 

Hello,

Can you post the schematic (or the part with the inductor)?
It could even be a 6 μH one.
The wire must be very thin when you say the resistance is 100 Ohms.
It will not carry much current.

Greetings,
Bertus

 

The size is 3/4" by 3/4" radial leaded, and has 007 stamped on the back, and was dipped in some sort of urethane material.

Does this help?

Aram

this picture may give you some sense about what it takes to produce a 5h inductor: it is 2.8"wx1.7"h and weighs a half a pound.

unless they had some super-duper technology back then to produce more inductance out of a tiny package, I would say that you take the baby to a rlc meter known to be accurate for a test.

 

Here you go... L102

I was floored with the size myself.. I still find it hard to believe.

Aram

 

the value is consistent with what it is supposed to do: control of bass.

but there is no way you can get that much H out of a tiny inductor like that.

 

Hello,

You are right.
It is the tone regulation part of a sub woofer amplifier.
The core of the coil must have a large μr.

Greetings,
Bertus

 

I was floored with the size myself.. I still find it hard to believe.

So do we, I suspect the manufacturer is publishing some bogus numbers. I've been wrong before, but that sucker is just plain too small for the rated size. You mention 36AWG wire, this could make a difference, since it would allow for a lot of windings in a small space. Being a toriod makes winding it harder though. I'll keep my eyes open.

 

Going through some web sites, it will take 5,649 windings on a T12 core, not a fun project, and that wire would have to be small.

http://www.66pacific.com/calculators/toroid_calc.aspx

http://www.elfa.lv/cgi-bin/index.cgi?artnr=58-732-03&lng=eng#desc

 

I know... I am physically hurting myself in order to make me accept the truth.



Aram

 

I know... I am physically hurting myself in order to make me accept the truth.



Aram

Can you post the dimensions of the coil and what you believe the core material to be.

I see no reason why this can not be 6 H. A quick look at the toroidal coil formula shows this to be feasilble. If you post the numbers we can double check.

The current will be very limited of course since current has a large impact on coil size.

 

Okay ... I sure appreciate you fellas help me..

The closest I can guestimate without removing the wire: the core is 3MM thick, the outer dia. 13mm, the hole dia 5 mm. Give it a few millimeters with the wire. The finished toroid is mounted on a cardboard or phenolic type material measuring .75 by about .75"

Once again 100 ohm resistance

Something still doesn't seem right.

Aram

 

6H is doable in small sizes, just means the wire diameter is very very small, kinda like the fine wire you find in the speaker of audio ear buds.

were toroidal inductors common during the time period of that schematic (1971)?

Also My friend Steve and I estimated the length of wire about 18 feet.

Aram

18ft?? thats not likely gonna yield 6H and 100Ohms no matter what diameter the wire is, you just cant physically make enough turns with 18ft. i question the 100ohms. what type of meter is reading 100ohms on this mystery part? 40ga is 1049ohms(dc) @ 1000ft. 100ohms would be roughly 10x less at about 100ft. 18ft is still a factor of 5x from that.

 

Also My friend Steve and I estimated the length of wire about 18 feet.

Aram

 

One interesting vendor

http://4sale.sbszoo.com/inductors.htm

Don'tcha love time warps?

 

One interesting vendor

http://4sale.sbszoo.com/inductors.htm

Don'tcha love time warps?

in a relatively small size, this site sells a 2H, but its 500ohms(dc). its very not likely that this mystery 6H inductor is just 100ohms (dc or Z), just aint gonna happen.

they also have:
3.4 H 92 Ω TENCO toroid
T-8757 HYDE 9100-2094 1-1/4" dia. x 5/8

this 3.4H is rather impressive @ just 92ohms(dc).