[GreenKeys] Measuring Electromagnet Saturation?

[Bob Camp]

Hi

I have a pretty good garage full of gear. I also have a fairly well  
stocked facility at work. I don't seem to have a gauss meter around  
the house, and don't certainly don't have one at work. If I don't  
have one and can't grab one, then recommending somebody use one is a  
bit much.

As far as measuring inductance with DC present or with an AC current  
source, it does work and it's commonly done. If you have a device  
with a closed flux path (like a toroid) it's not a bad way to do it.

Bob


On Jul 30, 2007, at 11:00 PM, WA5CAB at cs.com wrote:

> Oh, good Lord.  You can't measure inductance with a DC source,  
> regardless of source impedance.  And the solenoid coil impedance is  
> just the DC coil resistance.
>
> Just measure the core flux density as you increase the magnetizer  
> current.  The last three-terminal Hall sensors I bought more than  
> ten years ago cost under $10 in unit quantities.  And would drive a  
> multimeter.
>
> In a message dated 7/30/2007 8:25:01 PM Central Daylight Time,  
> ham at cq.nu writes:
>> Well assuming we are still trying to measure, rather than compute the
>> value:
>>
>> Drive the coil with a high impedance constant current source. Then
>> either measure the inductance or impedance. A fancy way would be to
>> apply fixed AC + variable DC current. Then you could monitor the
>> voltage on the coil with your 'scope.
>
>
> Robert & Susan Downs - Houston
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