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Powerful Solenoid Design

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Dear engineers,
I want to build a powerful solenoid yet very fast and of a stroke of 50-80mm, Kind of like this one but with more torque and speed with a return spring, Since I need a trigger and another 4 seconds to prevent a re-trigger I was thinking of using a super capacitor, When a trigger happens the super cap delivers a jolt to the solenoid giving a powerful and fast blow and recharges again and wait for the next trigger, This is a project for a rodent trap, the solenoid's core or rod will deliver a powerful punch and retracts when the charge is depleted, the recharge begins, the rodent drops and trigger is set again for the next catch.
I just don't know where to start, what kind of wire gauge, number of coils, what high voltage, what super cap and what circuit to charge it with?

Super Caps aren't designed for fast charge or heavy discharge. They are more like a really poor excuse for a battery to hold up volatile memory or supply power during momentary power interruptions. Most Super Caps want to see a charge cycle of not less than 20 to 30 seconds. For power you would want at least a gelcell. Even the 12v 12ah batteries can briefly push 30 to 40 amps and still maintain 10 volts. Seems like a lot of trouble to kill rodents. Aren't there already 100 solutions on the store shelves?

I'd try a conventional electrolytic cap that discharges into the solenoid via an SCR, with a reverse diode in parallel with the solenoid so the inductance doesn't charge up the cap in the reverse direction. Circuitry and operation is similar to an automotive capacitor discharge ignition. Seeing the current only flows for a moment, you could give the solenoid quite a pulse without overheating.

The capacitor discharge units used by railway modelers to fire point motors might be worth a look

What's that saying about a better mousetrap?  ;)

This is kind of a mechanical engineering question first and foremost, the electrical engineering would come after you determine the mechanical requirements of the solenoid.  I would actually question whether a solenoid is what you want at all here.  A solenoid like the one in the linked video operates at hundreds of watts.  Increasing the speed requires increasing the force to accelerate the moving part, and increasing force requires increasing power.  Using a motor to wind up a spring that provides the required force when released might be a better fit -- there are very large automatic circuit breakers that use this method, for example. 


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