[AT] testing a coil

pga2 at hot1.net pga2 at hot1.net
Tue Mar 21 14:20:26 PST 2006


Oops! slight typo on my part. :o(

Phil

----- Original Message -----
>From    : Chris Britton <c.britton at worldnet.att.net>
Sent    : Tue, 21 Mar 2006 13:24:56 -0500
To      : at at lists.antique-tractor.com
Subject : [AT] testing a coil


>Sorry Phil.. if you only get 5-6 ohms on the secondary.. you have a bad 
coil.. more like 4-7K ohms...

>Yes. The lowest Ohms range. You'll only be able to test for continuity
>on the primary side, should be about 1 Ohm or less. The secondary will
>be a little higher, maybe 5-6 Ohms.
>Phil

>From: "Dean VP" <deanvp at att.net>
>About all you can determine with a VOM on a coil is whether it is open or
>completely shorted.  Use the lowest resistance reading you have on the VOM
>since the coil will measure 0.6 to 1.5 ohms depending on its application. 
>If
>it has high resistance the coil has developed a break in the wire 
>somewhere.

Don't forget the hi-Z/ohm secondary.. as stated above..


> Another thing you could run
>into is a coil that has an internal resistor for use in a 12 V system but
>runs at 6V.

I'll bet you will be hard pressed to find a modern coil that actually 
includes a resistive element, as opposed to simply having a primary winding 
of sufficient length and gauge for the specified ohm value for the primary.. 
remember.. lenght and gauge of a wire effect it's dc resistance.  If you 
want a 3ohm primary for a 12v application, it is much easier to simply have 
the correct lenght/diameter copper wire than use some lower amount and a 
resistive ( power wasting/ heat generating) element...  Makes for easier 
coil manufacturing process as well.


Soundguy 


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