When I close the circuit, the lock opens, but when I open the circuit, most of time it stays in in the same position and I need to tap the lock slightly. I think there's a small magnetic field yet inside and the spring is not powerful enough to release the lock.
Is there an electronic workaround to uncharge the lock so that it can release itself?
I tested 5 mini locks (12V) and they have all this problem.
Reverse the voltage?
To attract the thing in the middle back in?
Don’t know if it will work.
Check the data sheet.
Yes, it's for doing that. It works 1 time on 10. The spring seems to be really the problem. I have a big lock that has not this default.
I tried by swapping + and - but it doesn't work
Maybe open it up?
And fiddle with the spring?
More likely there's a burr or other interference causing it to 'hang' out.
Does the lock open on its own if you disconnect it from your circuitry?
Can you post a schematic?
I had one of these (cheap model from the Far East) and the issue was mechanical, the moving piece was getting stuck because it was not pulled-in straight
I poured a bit of silicon based oil into the moving pieces and then it was working fine
When I use it without current it never stays blocked inside, it happens only after using with current.
Ok, I will try to add oil...
the current pulls it in really hard, it's easy to get misaligned - double check that if you can (that was my issue but may be it's something else)
As I said, if I put the thing inside with my finger, I can try hundred of time, it will never stay blocked. It's only after a magnetic field
Tap it in with a hammer, because that's what a magnetic field will do. A finger push is delivering the push with 1/4" of soft, mushy goo as a buffer. If it still doesn't jam, look for other solutions, but I'm still betting on mech interference/fit in some way.
No, it's the reason of my question, why?
No need schematic, the lock is directly connected to 12V 2A DC, there's nothing else.
The concept of discharging an inductor is a misnomer. It will discharge itself very quickly. Do you have a revere bias diode across it to cut down on the interference?
Reverse voltage will do nothing. Because it is an electromagnet and that pulls in just the same.
The possible causes are
I agree with you, it's certainly a mechanical problem but almost impossible to reproduce.
Here's a demonstration:
I will add WD-40 to help the spring
(It's really a shit from China)
I looked at your demonstration of residual magnetism. As already mentioned, a good demonstration of the use of wrong material in your latch. AC may or may not fix it. All depends on what part of the AC cycle the circuit is opened. If opened when the current is max and the magnetism is max, then you have the same problem as now.
Try a drop of light machine oil on the plunger. Don't use WD-40, it doesn't leave any residue.
Examine the plunger closely for a wear mark that could indicate a burr on the frame stamping. An emery board or small metal file can clear the burr.
My concern was whether your circuitry was completely cutting the current off, or whether a small current was still being allowed to flow. It takes much less current to hold a solenoid in that it does to pull it in.
Given that in the video he pulsl the wire away there is for sure no current flowing. That likely points to a mechanical issue probably.
There's no doubt now about a residual current...
Have you looked at the spring at the back? Could it get stuck compressed ?
