[GreenKeys] Measuring Electromagnet Saturation?

[Bob Camp]

Hi

The setup is pretty simple.

Take two coils in series and run current through them. Ground one end  
and bypass the end the power supply is connected to.

Then you measure the inductance and the "center point" with a fairly  
normal inductance bridge.

The net result is that you can run the current up and watch the  
inductance drop.

There also are ways to saturate the coil and then watch the spike as  
you break the circuit. The pulse contains the energy stored in the  
coil ...

Bob


On Jul 30, 2007, at 12:02 PM, Brooke Clarke wrote:

> Hi Bob:
>
> I've been doing my homework on electromagnet saturation and found  
> Electrical Silicon Steel as used in transformers, motors and newer  
> electromagnets.  Not only higher saturation but also less remnant  
> magnetization.  That's what's used as the core of the  
> Synchronization coil in the WU 37SS clocks with the Sweep Second  
> hand.  They were synchronized once a day using what looks like a  
> Teletype loop running at 120 Volts and adjusted to 1/4 amp.  A one  
> second pulse that ends at the top of the hour was used.
>
> In trying to come up with a circuit to drive the sync coil I'd like  
> to have a way to know that the electromagnet is in saturation.
>
> Any thoughts on a test that would demonstrate saturation of the  
> electromagnet?
>
> Have Fun,
>
> Brooke Clarke
> http://www.PRC68.com
> http://www.precisionclock.com
>