I Finally Got My Pulse Motor Running (Reed Switch)

Hook

I believe I got it – pulse motor or reed motor. After burning up the last one I was nervous, but this time the reed switch motor actually spins on its own power. Not fast, but it’s moving without my wrist flick. Totally cool man.

Watch this experiment

We fire it up for about five minutes, watch the voltage climb from 15.3 volts with zero amps all the way to 24 volts while the rotor keeps turning. You can see the levitation and the central bearing doing their thing. I even jack it up and it still runs until I back it down so it doesn’t cook.

What you'll learn

You’ll see a non-standard magnet layout that actually works, how a single solenoid drives it, why the reed switch likes a wood stick instead of steel, and roughly how fast it spins. Plus the plan to use this as the base for a magnetic double helix sculpture.

From the bench

I’m running it on a combination of levitation and a bearing in the middle. The reed switch is mounted on a plain wood stick – that runs better because there’s no magnetic interference. Put it on a steel pole and you’ll probably get interference that messes with triggering. One solenoid magnet 25 N is all it takes. I can’t clock exact RPMs but it looks like it’s going maybe a hundred RPM. We are not going to be able to go faster so we back it down and let it spin on its own power.

How it works / what we changed

The last build burned up, so this time I kept the reed switch away from metal. The rotor uses a weird pattern instead of the usual four or eleven magnets I’ve seen. It’s a 1-3-1 arrangement that gives eight magnets all together. When the magnet passes the reed switch it triggers the pulse, the solenoid kicks, and the rotor keeps turning. We also talk about adding weight – one flywheel should be fine even if I’ve seen heavier ones on other builds.

Magnet array pulse motor

This is by no means your standard magnet array pulse motor. I’ve seen a lot of fours and one with eleven. This one has got three one three one so it’s got eight all together. Totally cool man it’s working. The pattern gives a decent push without needing a ton of magnets.

Pulse motor solenoid

We are using just one solenoid magnet 25 N. That single pulse motor solenoid is enough to keep the rotor turning once it’s up to speed. You can hear the pulse and see the rotor accelerate when I increase voltage. It draws almost nothing – microamps at 17-20 volts.

24 magnet pulse motor

Even though I call it a 24 magnet pulse motor in some notes, the working rotor only uses eight magnets in the 1-3-1 pattern. The “24” probably comes from thinking about future node counts or the video title that mentions a 24-node version. This build is the simpler eight-magnet proof of concept that still runs nicely on one solenoid.

Pulse motor magnets

The pulse motor magnets are arranged in that 1-3-1 pattern around the rotor. They’re strong enough to trigger the reed switch and react to the solenoid without locking up. When the magnet is going to attract on the way back it can slow things down hardcore, so timing is everything. These same magnets will get reused as the base for the magnetic double helix sculpture.

Builder checklist

• Reed switch mounted on wood stick (avoid steel to prevent interference)
• 1-3-1 magnet array totaling eight magnets on rotor
• Single 25 N solenoid for drive
• Levitating rotor with central bearing
• Start at 15 V and watch current (zero to microamps)
• Have a way to back voltage down before it overheats
• Test for at least five minutes to see if it holds

Troubleshooting

If it doesn’t spin, check the reed switch alignment – it has to see the magnet clearly. Steel nearby can cause magnetic interference and stop triggering. If it burns up like the last one, lower the voltage sooner. The attraction on the back side of the pulse can slow it hardcore; make sure the solenoid is positioned to push more than pull. Adding too much weight at once (flywheel on flywheel) might stall it, so start light.

Safety

This thing is built to withstand 12 V but we ran it at 15-24 V. Watch for heat – I kept saying it’s gonna burn out. Keep fingers clear of the spinning rotor and magnets. When it’s running on its own power it can surprise you how long it coasts. Always have a quick way to kill power if it starts smoking.

FAQ

Why wood instead of steel for the reed switch?

Wood has no magnetic interference so the switch triggers cleanly. Steel throws it off.

How many magnets are you actually using?

Eight total in a 1-3-1 pattern. Not the full 24 you might see in other videos.

What voltage and current does it draw?

Starts at 15.3 V with zero amps, climbs to 17.5-24 V at microamp levels.

Can it handle added weight?

One flywheel seems OK. Multiple stacked flywheels add a lot of inertia and might stall it.

Will this become the double helix sculpture base?

Yes – that’s the plan. The levitating rotor and working pulse give a perfect spinning platform.

Related on this site

• How to Build a Pulse Motor: Complete Beginner's Guide
• Pulse Motor Rotor Design: Magnets, Materials and Balance
• Using a Hall Effect Sensor in Your Pulse Motor Build
• DIY Low Cost Pulse Motor Build with 16AWG Coil
• 24-Node Magnet Array Pulse Motor — Single Solenoid Design
• Minor Adjustments, Major Results — Pulse Motor Optimization

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