My best guess is that you are planning to to the right thing, a 24V
coil contactor is likely correct, and you are also correct that you
can use the L3 contact instead of another NO contact.
Had you told us from the start that there is a 24V transformer we
would have come to the conclusion much quicker. Instead you fed us
details piece by piece, which makes it incredibly difficult to build a
picture of what you have there.
However your voltmeter reading indicates that there is no voltage
_across_ the coil. The coil only gets energized if there is a voltage
difference, that's why you should place the black probe on one side
and the red on the other. If both sides of the coil have the same
voltage it is like a bird sitting on a high tension wire - it is not
energized.
Your contactor may be good after all. You must find out why it is not
energized.
My guess now is that you are looking at a pressure washer with a
trigger button on the gun. This trigger button is on a 24V circuit for
safety reasons, and that is also why you have the transformer and 24V
contactor.
Again, you must find why the coil is not energized first, unless you
see a voltage across the coil a new contactor will make no difference.
I repeat this because you sometimes seem to be hard to instruct. ;-)
At least this is a German built pressure washer and so it is likely
worth our time fixing it up.
ST
On Thu, Jul 19, 2012 at 1:24 AM, jimybud <jimybud@casscomm.com> wrote:
>
>
>
> You Advised:
> so connect your voltmeter set on ACV to the terminals of the coil and switch the washer on You will see what voltage is applied to the terminals and can buy a contactor accordingly.
>
> I did not perform this exactly as you suggest. I placed my black test lead on one of the two secondary coil wire from the transformer (this was a grounded wire). I then placed my red test lead on each side of the coil terminal of the contactor. My reading was approximately 30 ACV on each side of the contactor.
>
> As important is that even though 30 ACV was passing through the coil of the contactor, the mechanical contactors did not connect. I am therefore a bit more convinced that the contactor is bad.
>
>
> You Advised:
> Don't worry too much about the contact ratings, this is a small contactor and they likely took what was available rather than designing to any particular requirement. Most likely any contactor you
> can find will do just fine as long as the coil voltage is right.
>
> I appreciate this advice. I plan to visit the scrap yard tomorrow and see if I can locate an discarded furnace with a three pole 24 volt coil contactor. Otherwise ebay has a few for less than ten dollars.
>
>
> The contactor that I am replacing as L1, L2, L3 and NO (normally open).
>
> The L3 contact is not used, but the NO has wires connected. I am assuming that the NO is just another contactor pole and that generic three pole contactor that does NOT have a NO pole will still work.
>
>
>
>
>
> ------------------------------------
>
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>
>
>
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