Re: Aluminium aka Aluminum Wire (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

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Date: Sun, 30 Sep 2007 19:56:56 -0700
From: Ed Phillips <evp@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Aluminium aka Aluminum Wire (fwd)

For measuring milliohm values, I found it much easier to put a DC power
supply with a current limiting adjustment across the coil under test,
and adjust the current limit to 1.0 Amps (and verify with a DMM).  Then
read the voltage across the coil with a millivoltmeter.  The voltage in
mV reflects the resistance in mOhms, and it's easy to get a 4-terminal
measurement.

Regards, Gary Lau
MA, USA"

	That's the method I'll have to use because my milliohmmeter has the inconvenient ranges of 5 and 10 milliohms and then jumps all the way to 0.25 ohms, 1 ohm, and 2.5 ohms FS.  The coil I want to measure is somewhere over 10 mOhm but much less than 0.25 ohm so can't really read the scale.  This particular device uses the 4 terminal principle - two exciting terminals and two measurement terminals with a rheostat to set the current on each scale.  Long ago I built a current regulated supply which puts out 1 amp to use in measuring the resistance of transformer windings and my DMM goes down to 200 uV FS so I'm in business.  All I have to do is figure where that PS is hiding at the moment.

Ed