Is it bad if your solenoids cannot travel their full distance (eg, underpowered)?

I hope this is an entertaining n00b question, have searched a little bit around but couldn’t find an “explain like I am 5” answer. I have a couple of these “push/pull” style solenoids;

They spec as needing 12-24 volts, and that lower voltages may make the action weak/slow. I have played with this and yeah; at 12v they are weak and sometimes slow (putting my finger on the shaft I can prevent it from fulling extending) but at 24v they are snappy and strong as heck. Sorry for using the words “shaft” and “extending” in the same sentence…

Question is: if I choose to under-power a solenoid and it can’t push or pull it’s full distance, is that bad, will it burn out the coil quicker over time or put some kind of strain on the circuit powering it? I’m assuming yes and that you always want your solenoids powered enough (and powerful enough) to fully push/pull their full designed distance. Am I right or “is it complicated”?

Cheers all.

Dang, no response in over a week shows I kind of messed up the original question, sorry.

I’m only new to using solenoids, so there’s a bit of magic to understand yet. Can anyone help to understand how to calculate how much current you should be supplying your solenoids (eg, based on the 2 ones I linked above, I imagine it comes down to how big the magnet/coil are, etc) ?

I’m noticing that for both of those solenoids I linked above, when supplied with 20V DC @ 1.0A, the solenoids are snappy (quick) but I can still easily stop the thing by putting my finger in front of it when it tries to move.

Is this normal on such a low voltage, or am I not supplying enough current (how do you know)? Or is it a very complex subject that needs research and I should go away and study stuff for a while?


@noofny, solenoids are not damaged by “underpowering” them. Instead, they won’t supply the force to the plunger that you might expect. Solenoids are really simple, consisting of a wire coil and a magnetic (ie steel) plunger. The coil will be rated at a maximum current and voltage and the force of the plunger will be specified at a given voltage and current. So, depending on your application, you will need to find a solenoid which can deliver the required force. And don’t forget that the plunger’s mass needs a minimum amount of force to move in the first place!

One thing to remember with any inductive component (anything with a wire coil typically), it that it will produce a negative voltage “kickback” or “flyback” as the magnetic field created by the applied voltage collapses when the voltage is removed. This kickback voltage can destroy the driving electronics if not suppressed with a diode, typically called a flyback diode. You can find plenty of stuff on this topic by googling “flyback diode”.

So, perhaps before throwing yourself into too much research, you can tell us what you are trying to achieve with the solenoid and we can give you our suggestions. :wink:


Also, if you’re putting your finger over the plunger when removing voltage from either one of those solenoids, you’re only fighting against the spring on the bottom, the magnetic coil only retracts the plunger, it doesn’t push it back out, so you won’t have the same amount of force coming out as pulling in, however, this is only in the “push” phase.

Looking at the specs for these, the small one has just over 1lb of pulling force, while the large one has just over 3lb, thats at full voltage (24vdc), both of these would be fairly easy to stop with minimal effort.

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