How to get a linear solenoid actuator to cycle?

[udtsith]

Hi,

I am working on a project with my daughter who is 10. We are trying to get a linear solenoid actuator (push) to continuously repeat (push/return...push/return). But all it does is push and stop. How do I get the wiring set up to enable the solenoid to automatically cycle? Thanks!

 

[Nidum]

A simple solenoid with a plain iron core is essentially a pull in one direction device . To make it cycle you need something else to power the return stroke . This could be simple gravity (if solenoid is vertical axis) or a spring .

Easiest way to make a single solenoid with gravity/spring return cycle is to have two trip switches - one at each end of stroke . This is a very reliable arrangement but there is no easy way of controlling the cycle time and they tend to run rather fast with small components .

There are though some ways of slowing the cycle down and getting a smoother action . Most easily implemented is the dashpot damper . Basically just a piston in a cylinder with a small air leak around the piston .

A simple electronic circuit which gives timed on/off periods could be used to give exactly the cycle time that you want .

Better in some cases to have two solenoids - one for push and one for pull .

Just another bit of nostalgia for older forum members - I once did something similar myself using a hand wound solenoid , a daspot damper made from a Smartie tube and trip switches made from bean can metal and screws - and it worked .

If this is for a school science type project don't be afraid to improvise !

 

[udtsith]

A simple solenoid with a plain iron core is essentially a pull in one direction device . To make it cycle you need something else to power the return stroke . This could be simple gravity (if solenoid is vertical axis) or a spring .

Easiest way to make a single solenoid with gravity/spring return cycle is to have two trip switches - one at each end of stroke . This is a very reliable arrangement but there is no easy way of controlling the cycle time and they tend to run rather fast with small components .

There are though some ways of slowing the cycle down and getting a smoother action . Most easily implemented is the dashpot damper . Basically just a piston in a cylinder with a small air leak around the piston .

A simple electronic circuit which gives timed on/off periods could be used to give exactly the cycle time that you want .

Better in some cases to have two solenoids - one for push and one for pull .

Just another bit of nostalgia for older forum members - I once did something similar myself using a hand wound solenoid , a daspot damper made from a Smartie tube and trip switches made from bean can metal and screws - and it worked .

If this is for a school science type project don't be afraid to improvise !

Thank you!