Re: 37XR inductance range

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Mike,

What are you measuring?  In general, any LCR type meter us useless on 
iron cored inductors or inductors that have a core with a significant 
hysteresis.  Since you inductance is relatively high, I assume your 
inductor is cored.

The core needs a certain minimal amount of energizing current to 
reach its normal magnetization curves.  Typical meters use very small 
currents that can't energize the iron and such properly.  The meter 
uses different current levels for different ranges so the readings 
vary, but the readings are probably far off anyway.

Probably best to run 60Hz AC voltage across it with a variac and 
measure the current.  Then you get   L = V / (I x 2 x pi x 60).

If you graph the inductance vs current, it starts out very low, 
reaches a long flat area and then drops again as the core saturates.

Cheers,

        Terry


At 11:51 PM 1/5/2006, you wrote:
> I recently purchased the Meterman 37XR per the list members 
> favorable use. I was just measuring the inductance of my variable 
> ballast, and a few hig power isolation xfmr I have laying around. 
> One measured 365 mh. When I changed ranges to henrys, it 
> dramatically changed to 0.260H ! Does anyone else notice this vast 
> discrepincy? Can I trust the meter?