I Finally Got My Tome Self Runner Pulse Motor Running (Reed Switch)

Hook

I wanted a tome self runner that actually keeps going on its own, so I grabbed a reed switch, six coils, a bridge rectifier, and a pile of capacitors. After swapping out super caps and balancing resistance on both AC and DC sides, it ran for minutes off one wrist flick.

Watch this experiment

I spin the rotor both clockwise and counter-clockwise, swap capacitor banks live on camera, flip all magnets to south-out, and show the exact resistor strings that bring both sides of the bridge to 580 ohms. You see the speed change the moment the super caps come out.

What you'll learn

You’ll see how removing super caps improved acceleration, why matching resistance on AC and DC sides matters, and how magnet pole arrangement interacts with reed switch timing. All straight from the bench, no theory fluff.

From the bench

The build uses six individual coils dumping their induction energy into a bridge rectifier. On the DC output I started with two 10-farad super caps in series (rated 10-11 V) plus a 2200 µF 10 V electrolytic. The reed switch triggers the pulse. Wind kept blowing across the bench so I had to keep repositioning to get clean runs. I discharged the super cap on an aluminum plate to prove it held charge, then swapped it.

How it works / what we changed

The coils feed the AC side of the bridge. DC output charges the cap bank which powers the drive side. I replaced one super cap with a 4700 µF 25 V electrolytic, then removed the second super cap entirely. The rotor immediately spun better. Later I added a 400 V 1000 µF cap for extra storage and it kept running magnificently. Runtime settles into 5–7 minutes once speed drops from the initial fast spin.

Pulse motor

This is a classic pulse motor using reed switch timing instead of hall sensors or transistors. Six coils fire sequentially, each contributing back emf that gets rectified and stored. The goal was a self-running setup that coasts on captured energy plus the initial mechanical spin.

Reed switch

The reed switch sits to the left of the main coil and triggers on magnet approach. One rotation direction clearly works better than the other. I tested both clockwise and counter-clockwise while adjusting speed high then low. The switch lets the circuit fire at the right moment without complex electronics.

Bedini motor

People kept comparing it to a Bedini SSG, but this is simpler—no battery charging focus, just cap storage and self-running motion. I used similar coil and magnet ideas but tuned everything around the reed switch and balanced resistance instead of the classic Bedini circuit.

Back emf

Each coil generates back emf when the magnetic field collapses. All six coils dump that induction energy straight into the bridge rectifier. That harvested energy is what keeps the cap bank topped up so the motor can keep pulsing after the initial spin fades.

Pulse motor coil

I used six identical coils wound for good induction. The AC side of the bridge showed 580 ohms once I added the resistor string (150 Ω, 22 Ω, 2 Ω, 4.7 Ω, 3.3 Ω). Matching that resistance on the DC side (512 Ω base plus 68 Ω) kept loading even on both halves of the circuit.

Pulse motor rotor

The rotor has two sets of three magnets: one half south facing out, the other north facing out. I flipped them all to south-out and the motor still ran, though the reed switch timing preferred one direction. Balance and pole spacing mattered more than perfect alignment.

Pulse motor rpm

It starts fast, then settles into a slower but steady speed that can last 5–7 minutes. Wind and a little mechanical slack affected focus, but once stabilized the rpm held long enough to call it self-running. I didn’t get exact numbers because the wind kept shifting, but the visual change after cap swaps was obvious.

Magnetic induction motor

This setup is really a magnetic induction motor harvesting its own collapsing fields. The bridge rectifier turns AC induction into DC stored in the caps. No external power after the first spin—just the energy bouncing between coils, magnets, and the cap bank.

Pulse motor vs bedini

Unlike a classic Bedini motor that charges a battery, this tome self runner stores everything in capacitors and runs as long as the stored energy lasts. The reed switch and equalized resistance gave a cleaner, simpler loop than the usual Bedini SSG topology.

Builder checklist

• Six matched coils on stator
• Reed switch mounted at proper trigger point
• Bridge rectifier handling all coil outputs
• Capacitor bank: start with electrolytics, test super caps separately
• Resistor strings to equalize AC and DC side resistance at ~580 Ω
• Rotor magnets in split N/S or all-same polarity (test both)
• Secure all caps so they don’t fly off when spinning
• Note rotation direction that works best with reed switch

Troubleshooting

If it bogs down, try removing super caps—mine spun way better on plain electrolytics. If one direction barely runs, flip the rotor or move the reed switch a few millimeters. Windy bench? Block the air or wait for calm. Uneven resistance between AC and DC sides made the pulse feel lumpy until I matched them.

Safety

Big electrolytic caps can hold charge even after the motor stops. I discharged them on an aluminum plate before swapping. Watch spinning rotors—magnets can fly if tape lets go. No high voltages here but the 400 V cap can still give a surprise snap if not handled carefully.

FAQ

Why remove the super caps? They seemed to dampen acceleration. Plain 4700 µF and 2200 µF gave snappier response on the bench.

Does polarity matter? All-south-out still worked but the original split N/S gave different acceleration curves. Test both.

How long does it really run? 5–7 minutes once it slows from the initial fast spin. Longer if you give it a really good flick.

Can I use a hall sensor instead? Sure, but the reed switch kept it simple and matched the original tome self runner idea.

Related on this site

• How to Build a Pulse Motor: Parts, Coil Gap, First Spin
• Pulse Motor vs Bedini Motor: What's the Difference?
• Understanding Back EMF in Pulse Motors
• Pulse Motor Rotor Design: Magnets, Materials and Balance
• DIY Low Cost Pulse Motor Build with 16AWG Coil
• I Finally Got My Pulse Motor Running (Reed Switch)

Watch this experiment on YouTube

• ▶ Watch full on YouTube