Old Wire Wound Resistors

[Wallace Gasiewicz]

Hope this is the appropriate spot to post
I recently acquired a bunch of old wire wound resistors New Old Stock

402.2 K  1/10 %

NAT. RES. Pearl River  New York

They are within specs still Measure 402.2 K  on my Biddle Bridge and all are very close in values on my HP 3456
About 1.95 Henries on my Genrad

Were these used in any equipment that anyone knows of?

[CaptDon]

I can't imagine the value of a high ohmage resistor with that much inductance.

[CaptDon]

It kind of occurred to me at 1.95 Henries that is a lot of wire. I see the 1/10th % rating on the resistance. I should think that would vary drastically with temperature change? I guess the wire could be a blend of different metals but I am not sure zero temperature drift can be obtained, at least within .1% across say 0c to 70c? Just pondering how this thing was used? Cheers mate, hope someone can chime in on its intended use.

[amyk]

I suspect they would've been used in vacuum tube circuits.

[Kim Christensen]

About 1.95 Henries on my Genrad

Are you sure that's an accurate measurement? Doesn't sound right to me at all.

[vk6zgo]

I suspect they would've been used in vacuum tube circuits.

Nah, resistances of such values would normally be the province of carbon composition resistors in the tube days
Most of the wirewounds used in tube gear would "top out" at a couple of hundred ohms.
The resistors concerned may have been used in DC bridges or something of that nature, where the inductance wouldn't have mattered.                                                           

[Jwillis]

Wire wound resistors are for low frequencies. Parasitic inductance increases with frequency.  Recheck your measuring frequency.  Best measuring frequency is around 100- 120Hz buy usually no more than 1 KHz.

I pulled out some old Soviet era wire wound resistors and measured the inductance of those . I pretty much ended up with the same results you did with a 300K resistor rolling in at around 2H at 100Hz then dropped off at 1K to around 400uH then again rising to 150mH at 100KHz. I suspect as the frequency increases to the Self Resonating Frequency the inductance increases then drops suddenly at the SRF. Then increases again as frequency continues to increase. Just what I observed with a very basic experiment.

Best use is DC applications.

[Wallace Gasiewicz]

The resistance on these is measured on several different meters and is quite accurate on all meters, including a DC Wheatstone Bridge. 402.2 K

The only thing I have that can measure the inductance is a Genrad 1650 LCR Bridge and gives the near 2 Henry reading, Genrad 1650 measures at ONE KHz
All my other instruments will not measure this high in inductance and read over full scale. I remeasured several times.
I also thought this reading was unusual.
I guess I could test at lower freq putting  external signal into my GR 1650

It looks like wire wound on a hollow bobbin, you can see thru the center. and the leads are soldered to small terminals on the bobbin. I did not take one apart.
About 2 cm in length, one cm dia.

I cannot figure out what it could have been used for either. I just picked them up because of the 1/10 % rating, to have something for a quick resistance check.
By the way it actually sez 1/10 % not .1%
Maybe Audio filter? But it is a resistor primarily since the inductance is not listed on the paper cover.
I also thought maybe a resistive divider??  In a DC test instrument, like a bridge. But with that value?

If anyone wants one or more . the shipping cost would be the biggest part of the bill. PM.

Thanks for the responses, it is absolutely amazing that all the responses are pertinent.  I just thought the resistors were interesting.

[Jwillis]

It looks like wire wound on a hollow bobbin, you can see thru the center. and the leads are soldered to small terminals on the bobbin. I did not take one apart.
About 2 cm in length, one cm dia.

I cannot figure out what it could have been used for either. I just picked them up because of the 1/10 % rating, to have something for a quick resistance check.
By the way it actually sez 1/10 % not .1%
Maybe Audio filter? But it is a resistor primarily since the inductance is not listed on the paper cover.
I also thought maybe a resistive divider??  In a DC test instrument, like a bridge. But with that value?

They're old vintage power resistors. Wire is wound on a ceramic tube then coated with ceramic glaze . Similar to below. 
They were used in many things. Radio, Television, Audio. Think I had a frequency generator that had one. Used a lot  in tube equipment. They didn't worry much about parasitics in that kind of stuff back then.

[vk6zgo]

It looks like wire wound on a hollow bobbin, you can see thru the center. and the leads are soldered to small terminals on the bobbin. I did not take one apart.
About 2 cm in length, one cm dia.

I cannot figure out what it could have been used for either. I just picked them up because of the 1/10 % rating, to have something for a quick resistance check.
By the way it actually sez 1/10 % not .1%
Maybe Audio filter? But it is a resistor primarily since the inductance is not listed on the paper cover.
I also thought maybe a resistive divider??  In a DC test instrument, like a bridge. But with that value?

They're old vintage power resistors. Wire is wound on a ceramic tube then coated with ceramic glaze . Similar to below. 
They were used in many things. Radio, Television, Audio. Think I had a frequency generator that had one. Used a lot  in tube equipment. They didn't worry much about parasitics in that kind of stuff back then.

400k ones weren't!

[Wallace Gasiewicz]

These are not coated, looks like they are covered with paper label and then translucent tape.

[Gyro]

No, those would have been for instrumentation rather than power. You didn't get 0.1% glazed power resistors.

I would say, voltage dividers, bridges etc. You often find slightly-off whole number values to allow for final circuit trimming / calibration.

[Wallace Gasiewicz]

Someone told me that National Resistance made primarily :custom: resistors
So they are probably for some special equipment . I agree that a bridge or some divider is a likely unit for these parts.
Thanks Gyro and all others.

[inse]

National Resistance is kind of a strange company name.
Sorry for being off-topic

[Wallace Gasiewicz]

National Resistance is kind of a strange company name.
Sorry for being off-topic

Yea, just try to Google it !!!!

[MathWizard]

I looked up Biddle Bridge circuit and found this gem

https://www.ietlabs.com/pdf/GenRad_History/A_History_of_Z_Measurement.pdf

[Nassau Cable]

Hello. Wire wound resistors are commonly used in high-power and precision applications due to their high stability and accuracy. Some common applications of wire wound resistors include power supplies, audio equipment, telecommunications, and industrial controls.

As for the specific brand "NAT. RES. Pearl River", it is hard to say which equipment they might have used in without more information. It is possible that they were used in a variety of equipment from that era, including military, aerospace, and industrial applications (cool, don't you think?)

About what to do with it, you could consider using them in your DIY projects or selling them to other vintage electronics enthusiasts.

[Wallace Gasiewicz]

I do have a Biddle Wheatstone Bridge and a GR 1650B Impedance Analyzer.
Thanks for the article. Nice summary.
I think these thing were used in a bridge.I think the wire is quite thin to achieve the high inductance in the small package, so I do not think they were  power resistors
I was just wondering if anyone knew which particular equipment they were used in, since I do not.
Someone on another group said that he had toured the National Resistance facility and that this company only made specialized resistors. Makes sense.

Wally

[donlisms]

I don't you suppose you have any kind of chamber or other devices you could use for temperature control, eh?  Finding even an approximate temperature coefficient could be a big clue to whether they are truly special, at least in some sense.

[Wallace Gasiewicz]

No oven, but I will try some hot air while observing resistance on my HP 3456.

[shapirus]

Hello. Wire wound resistors are commonly used in high-power and precision applications due to their high stability and accuracy. Some common applications of wire wound resistors include power supplies, audio equipment, telecommunications, and industrial controls.

I may be witch-hunting, but doesn't this user look exactly like chatgpt? Check the previous posts. Do you notice that all of them have somewhat of a rather prominent common pattern?

[LinuxHata]

These were used in photomultiplier tube circuits, as I remember.