Re: Bench testing solenoids...the right way...advice please

Posted by HH56 On 2023/2/24 17:34:27

I have never found a spec for resistance but I suspect the coil ohm values will be so low they will be hard to check with a typical ohmmeter. On both solenoids the pull in coil is wound with a heavy gauge wire so will read almost a direct short between the terminal and the case. The hold coil is wound with thinner gauge so might read a few tenths of an ohm but no idea what the value would be. An actual open for either coil would be the only definitive test I think you could be sure of.

On the R-11 solenoid the coils are in parallel and both connect to terminal 4. The only way to individually check them would be to measure from the terminal to the case to get a reading and then pull the plunger out by hand to open the turn off contact and disconnect the pull in coil. I have never tried it but logically there should be a small increase in the ohm reading when the heavy wire pull in coil path is opened.

On the R-9 the coils are individual so checking from 3 to case will get the hold in coil value and from 4 to case would be the pull in coil.

On both solenoids the disconnect contact does open the pull in coil path and should have 0 ohms across it. Since it is a service item exposed to arcing and burning, if that has happened there could be a resistance or an open that should not be present and would warrant investigation..