Fastron 18mH Inductors from Mouser

[GOR3]

I just received a dozen Fastron "18mH" inductors from Mouser, mfg'r p/n 07MFG-183J-50. In attempting to match them, they all measured between 9.2 and 9.8 mH. To measure them, I used a Chinese-via-eBay LCR meter. The meter has proven quite accurate for capacitors; this is the first inductor I've measured. Has anyone else had problems with these inductors (or LCR meters)?
Thanks,
George

 

[grimberg]

According to the data sheet the nominal induction is measured at .02 MHz. Consult your LCR meter's manual. Most likely the frequency it uses is 1KHz.

 

[davidsrsb]

18mH can be measured at 1kHz and inductance is likely to be similar or even a little higher at the lower frequency. Are the parts marked?

 

[abraxalito]

Check the stimulus amplitude - the maximum current for these inductors is rather low. From memory around 10-20mA so your meter may well be overloading the part, driving it into non-linearity.

To see if excessive stimulus is causing a problem, try measuring two inductors in series, then two in parallel. In series the inductances should add (36mH) and in parallel the combination should be half the nominal values (9mH).

 

[GOR3]

davidsrsb, the parts are not marked.
Abraxalito, good suggestion. I will give it a try.
Thanks,
George

 

[EUVL]

A (hand-held) LCR meter with 10mA test current ??


Patrick

 

[GOR3]

Patrick, I was hoping you might see this. As you might have guessed, the inductors are for the Gerhard filters on the ACKO boards which I bought from ACKO. Do you know the method by which your group matched the inductors?
Thanks,
George

 

[EUVL]

We use a hand-held "Chinese" LCR meterto match.
Absolute accuracy is not important for matching, just repeatability

And no problems at all.
All inductor within manufacturer's tolerance, as you would expect from the Germans.


Patrick

 

[GOR3]

Sehr gut!