Next Coil Basically: Chaining SSG Coils on My Pulse Motor

Hook

I took three bini style coils, wired the school girl circuit on each, and ran the negative spike from one straight into the next. The next coil basically powers the one after it. No idea if it's the best move but it spins up to 655 RPM and the lights flash like crazy.

Watch this experiment

We start with three coils on the same rotor. Each has a 26-gauge drive strand and a 30-gauge trigger strand. School-girl connection to its own transistor. Then I route the collector of the third transistor through a diode and back to the positive of the power supply so the spikes chain forward.

What you'll learn

How to chain SSG coils so each negative spike powers the next instead of pulling from the battery. What happens to the lights, how the reed switch changes things, and why the current rotor might need work.

From the bench

Three 1000-turn bi-filar coils sitting on the pulse motor. One drive, one trigger per coil. First two coils run normal SG, the third collector goes through a diode and feeds the next coil. At 12 volts the rotor barely turns until I give it a push. Lights stay dark until I disconnect the SG circuits from the supply; then they light up from the spikes alone.

How it works / what we changed

When the coils are chained the negative spikes generated by one coil become the power source for the next. Instead of every coil pulling from the battery they're connected in series through the spike path. I unhooked the SG circuits from the supply and the lights came on bright. Later I plugged the end of the third coil into the reed switch and the lights started flashing in time with the magnets passing.

Make new rotor

I want to get a trigger coil hooked up on this one but the current setup isn't firing the trigger reliably. I might have to make new rotor because the beautiful one I have just isn't working. It's not firing the trigger at speed even though the motor will run.

New rotor mean

New rotor mean I'd have to build or swap the magnet wheel so the timing lines up with the trigger coil I'm trying to add. The existing rotor is balanced and looks good but at 550-655 RPM the trigger signal isn't consistent enough for the reed switch or hall setup I want to run next.

Better coil

Got to get a better coil for that. The present windings aren't giving me clean trigger at higher speed and the motor needs a shove to start. I'm going to roll some more coils except this time I'm adding an extra strand. They'll all have 32, 30, and 26 gauge. The 30 still works really good for trigger on this rotor so the 32 will be for generation.

Coil hooked

I want to get a trigger coil hooked up on this one. After the reed switch test I routed the third coil back into the power distribution block, got a steady 560 then 643 then 655 RPM. When I plug the circuit back into itself basically all the lights go off but the motor keeps running. The coil hooked this way runs cleanly on its own spikes.

Builder checklist

• Wind three (or more) 1000-turn bi-filar coils: 26 AWG drive, 30 AWG trigger
• SG connection on each transistor
• Route collector of final transistor through diode to next coil positive
• Test with reed switch on the last coil
• Measure RPM before and after re-routing the output
• Prepare 32-gauge wire for next set of coils if you want a dedicated generation strand

Troubleshooting

Motor won't self-start at 12 V — give it a push and check coil gap. Lights stay off until SG circuits are disconnected from supply. Trigger not firing — current rotor timing is off; may need to make new rotor or adjust magnet placement. Readings jump around — I didn't get a perfectly clean reading every time but it climbed steadily to 655.

Safety

Running at 12 volts, spinning rotor with magnets, diodes handling spikes. Keep fingers clear of the rotor. Watch for heating in the transistors when lights are fully lit. Disconnect power before changing wiring.

FAQ

Does chaining the coils kill the battery faster? In this test the lights run off the spikes and when looped back into itself the lights go off but the motor keeps running.

Why add a 32-gauge strand? 30 gauge works great for trigger on this rotor so the extra 32 will be just for generation.

Can I run this without the reed switch? Yes — it ran on the SG circuits alone but the flashing lights and clean trigger are nicer with the reed switch.

Related on this site

• How to Build a Pulse Motor: Parts, Coil Gap, First Spin
• Bedini Motor & SSG Circuit Guide (Beginner Bedini Explained)
• Pulse Motor Rotor Design: Magnets, Materials and Balance
• How to Wind Coils for a Pulse Motor (Step by Step)
• Best Wire Gauge for Pulse Motor Coils (AWG Guide)

Watch this experiment on YouTube

• ▶ Watch full on YouTube