Making An Overpowered LEGO Solenoid Engine

See my latest experiments and behind-the-scenes footage!

Solenoid engines are a lot of fun to build, so let’s make one using Lego, and an overpowered solenoid module!

The principle is simple - solenoids consist of an electromagnet that pulls a piston into the coil. We can leverage this movement to drive a crank shaft in an engine, turning the movement into rotation. So let's build an engine powered by this powerful solenoid and see if we can drive some Lego inventions with it.

[xyzabc]

That sound. I'm imagining this engine powering a locomotive hauling a few rail-cars around a Lego track loop.

[tonyiliffe]

I would strongly suggest adding a reverse biased diode across the solenoid to avoid burning the switch out from the back EMF. When you suddenly remove power from any large inductive load a brief high voltage is induced. Your switch appears to have a transparent body, if you turn all the lights off you will almost certainly see sparks (arcing) inside the switch, this will burn it out, or cause it to stick 'ON' fairly quickly, a diode will short this out and protect the switch. It would be better still to use a power transistor (2N3055 or similar) to drive the solenoid and hence protect the switch completely.

[stormstubbenrgaard]

7 more solenoids and then make a solenoid v8 engine.

[gydo]

The engine with the big flywheel is a PERFECT example of why you need timing advance. See how the solenoid only fires after the 'piston' is past top dead center and the solenoid needs to 'catch up' with it? That's lost potential, which can be harnessed by moving the switch 'trigger point' a few degrees at higher RPM. This is a great demonstration of this, well done!

[RedShift]

Make one with two reciprocating solenoids. MORE POWERRRR

[malhardeadshot]

it would be even better if there is a physical connection between the solenoid and the piston rather than pushing it, so that it will provide power even when the solenoid is returning because of the spring

[legomotogp]

Jamie, this is amazing! The way you tamed that giant solenoid and turned it into a functional Lego machine is impressive. I really liked:

The clear explanation of the building process.
How you used the switch as a timer.
The addition of the flywheel to smooth out the power.
Seeing it move that little tank was a perfect demonstration of its power. Great job!

[matthewscarpetti]

A hit and miss engine would be a terrific use case for this, all you need is a second microswitch and a governor

[mushroomcraft]

Electric motors in some parallel universe:

[CJ-wefv]

Remove the spring in the solenoid, setup a second lobe at a 180 degree offset that reverse the polarity to the solenoid, as well as a direct connection from the solenoid to the connecting rod, so it pushes and pulls

[adonisengineering]

This is a great demo on how literally a steam locomotive is able to move itself.

[Anonymouzor]

you could add a centripetal governor for the speed to limit the firing of the solenoid, making it act similar to a hit and miss engine

[Infinite_X]

It reminds me of a traction engine with the big flywheel. Could maybe make a lego one?

[EliHowell-yqnp]

Next video: see just how powerful you can make it by adding more cylinders

[ScarlettStunningSpace]

I cannot get enough of Lego engines <3

[bradleyj.fortner]

It reminds me of the big steam engines that used to run factories. The big engine would run a long shaft that would power all the individual machines via belts and pullies. So, use it like one. You have enough power there to make it do several jobs at once. Make an amusement park or a Rube Goldberg machine. See how many things you can make it do.

[TheVeryPurblePiper]

You should try adding a rear wall on the solenoid too so it doesn't just blast back entirely, whereas it can absorb more of the blast and stuff if you were to pull the wires through a similar piece to the one(s) on the front and then add some foam inbetween so it doesn't sledge itself out!

[xmysef]

Hey, that’s a cool engine!

However, I have realized something. The spring used to return the rod back to it’s starting position is taking energy from the solenoid, and then dissipates it into heat because the return-stroke of your solenoid isn’t utilized by the engine. Just a thought!

[dosh]

This engine reminds me of the big monocylinder used for farms or industrial task. The ones where the flywheel also served as a pulley.

[Hnkka]

2 of these solenoids and make old steam train, they have "one" on both sides driving the wheels forward. It would also sound cool