[Milsurplus] Triad Choke

[John Hutchins]

Richard, all -
Question would it be as effective ?  to use a safer voltage say a 10V to 
12V AC transformer to supply the measurement
Voltage and current?

-Thanks
Hutch

On 12/27/2010 4:44 AM, Richard Brunner wrote:
> More:  Measuring a power filter choke on an inductance meter is not
> useful because the inductance goes down substantially when dc passes
> through, as in service.
>
> Measuring choke characteristics is easily done.  Use most any power
> transformer with full wave rectification and no filtering.  Connect the
> test choke in series with a resistor R of several thousand Ohms, and a
> milliammeter from + to the transformer center tap.  Varying input
> voltage, measure ac voltage across the choke, and resistor, and dc
> current.  Then:
>
> L = (Echoke x R) / (Eresistor x 2 x pi x f)
>
> For 60 cycle input with full-wave rectification, 2 pi f becomes 2 x 3.14
> x 120, or 754
> Now L = (Echoke x R) / (Eresistor x 754)
>
> Measure ac voltage with an average reading (VOM) meter.  Use a blocking
> capacitor to keep dc off the meter.
>
> As you increase the current you will see the voltage increase levelling
> off, indicating you are getting into saturation, and is approximately
> the useful current limit.
>
> References:
> "Measuring Inductance of DC Loaded Chokes," J. H. Ellison, W6AOI, QST,
> Feb. 1963 pp16, 17.
> "Know Your Filter Choke Coils," Harold Reed, W3EJP, CQ, Nov. 1959, pp
> 50, 51.
>
> Richard, AA1P
>
>
>
>
> On Sun, 2010-12-26 at 13:08 -0500, n2lxm at juno.com wrote:
>> Good Afternoon All,
>>
>>          While looking through the supply closet for a project on the
>> bench I found a Triad choke I can't ID. The only markings on it is 30L4.
>> I guess I had measured it on a LC Meter at one time, as there's a note on
>> the bottom of 11 Hy. Can Anyone ID this choke, I really just need to know
>> the current rating. Thanks, and I hope everyone had a Merry Christmas.
>>
>>
>>                                  Jeff N2LXM
>>                    AMATEUR RADIO OPERATOR
>>                                  AMERICAN
>>                                    PATRIOT
>>                    Proud Father of two US MARINES
>
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