Add a diode to my solenoid valve?

[k0ua]

I too would think that excess current would open the (shorted) diode junction again, but I have never seen a failed open diode, and if I did, I don't remember.

I suspect the OEM ford coils were wood and the later version, like I bought in 72 or 3 were plastic.

I have seen plenty of open diodes. I even saw one disc ceramic capacitor that was a semiconductor. I supposed it formed naturally somehow. Only one of those though in 50 years of trouble shooting.

 

[dfkrug]

A solenoid will ordinarily operate the same with either polarity even if there's no diodes in it. It just tries to center the iron plunger in the magnetic field. The polarity doesn't matter unless the plunger is a permanent magnet, which isn't common.

I stand corrected. Rectifiers are included inside only solenoid coils intended for A/C signals, a common type. None that I have
owned have permanent magnets inside as far as I can tell. So either polarity DC usually works with DC coils, and any switch
protection diodes would likely need to be installed externally by the user. I use them.

Some solenoids come with one side grounded. Others may state a polarity for DC. In those cases, there MAY be an
internal diode. When all else fails, consult the documentation.

 

[Texasmark]

Good to know about the old ignition.

So (silly me) has to wonder, if you don't have a diode and not a set of fingers to go through, what happens to that energy?

I too, learned that unpleasant shock from my 150 in one electronics kit.

It usually dampens out in 11 cycles exponentially dissipated in the resistance of the windings of the coil and the permeability of the core......with the external circuit open so that no current flows.