[Test-Equipment] Need Recommendation for LCR Meter

[DW Holtmnan]

Hello,

A digital Cap meter powered by a 9 volt battery will not test high 
voltage breakdown on caps. That is not what it is designed to do. It 
only applies a very low voltage to make measurements.The Sprague TO 
series of checkers are designed to test caps by applying a high 
voltage.  I use an old military crank Megger that will show resistance 
with around 400 Volts applied. Old paper caps fail the high voltage 
tests at around a 95% rate. A new orange drop or a good (new or old) 
mica basically shows infinity when measuring resistance. I just throw 
out all old paper caps, I think that they are a failure waiting to 
happen. The best test for Black Beauties in my opinion is to listen to 
the klunk they make when hitting the bottom of the trash can. I know 
that there are lots of opinions on this subject, this is mine.

Digital caps checkers however work great for telling you the value of 
caps. They also do the same for inductors.

Best,
DW Holtman


Edward Knobloch wrote:
> Hi,
>
> You can go badly wrong believing a digital capacitance meter.
> I used a B&K model 830 digital capacitance meter to measure
> a bunch of old "Black Beauty" capacitors (Sprague paper tubulars).
> All of the digital measurements were in the right ballpark,
> and the capacitors had previously shown d.c. open circuit 
> (greater than 30 Meg Ohms) using a Fluke model 75 DMM.
>
> Out of curiosity, I broke out my old Sprague TO-4 capacitance bridge.
> The eye of the bridge did open at the right place on the scale,
> but the eye did not indicate a good null - it looked fuzzy,
> compared to its appearance when testing a good mica or ceramic capacitor.
> I then tried the insulation test feature of the Sprague TO-4, 
> and all the paper capacitors tested failed -  all were below 150 MegOhms
> when tested using a moderately high voltage.  (Sprague says a small value
> paper
> capacitor should have an insulation resistance greater than 5000
> MegOhms.)
>
> Short answer: a digital capacitance meter will give you an accurate
> capacitance value of a good capacitor, but can't tell if the capacitor is
> leaky.
> An old bridge like the TO-4 will test the capacitor under some stress 
>  - the TO-4 has either 85vac or 150vac across the arm - 
>  so leakage will show up.
>
> By the way, I had previously changed out all the paper tubular capacitors
> in the Sprague TO-4 to Orange Drop mylar capacitors during refurbishment
> -
> that's where I got the tubular capacitors to test!
>
> 73,
> Ed Knobloch
>
> On Mon, 4 Dec 2006  "Ken Woodside, WB8EQO" 
> <wb8eqo at yahoo.com> writes:
>   
>> I am looking for a decent meter to measure inductance,
>> capacitance and resistance. Any recommendations on
>> what to buy? I was looking seriously at the Ocean
>> State Electronics 1810 but know they are in turmoil.
>> Many thanks in advance!  Ken  WB8EQO
>>
>>     
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