Paul Drahn wrote:
On 4/15/2013 9:31 AM, Steve W. wrote:
Tom Gardner wrote:
On 4/15/2013 3:43 AM, Steve W. wrote:
Tom Gardner wrote:
I'm out of my element trying to test AC valve coils. Usually, If they
fail on me they smoke and crack and smell VERY bad...or, they have no
continuity. But, I've had some go bad with none of those obvious
symptoms. I Googled and for some of the testing methods you need a
magnetomatrix oscifier and capatrometer. There should be an easier way!
inductive ammeter - with AC applied if the coil is conducting at all you
should pick up the amp draw.

Compass and switched DC source. Switch so you can cycle the power to the
coil. Compass to tell if the coil is generating a magnetic field. (Use a
pulsed DC source with a low cycle time for best results)

VOM, non-contact thermometer and the data sheet for the valve.
VOM to measure the resistance of the coil.
NC Therm. to measure the temperature of the coil.
Data sheet to tell you what the correct number should be for a given
temperature.

Does it make a difference if the coil is " satisfied" with a core?

Cores won't make much difference for the electrical tests. The magnetic
ones could be a problem due to the core retaining magnetism.

But don't ever power one up without the core! That quickly lets out the
magic smoke!
Paul

Low voltage DC won't hurt it as long as it's pulsed. The coil will act
like a simple choke then.

--
Steve W.