Bedini Does Spike: Speed Increases Through Induction in Three Magnet System

Hook

I pulled the plug on a charged cap bank and the rotor just kept getting faster. The Bedini does spike was feeding everything back through the coil positive end and the speed climbed even below 10 volts. No battery, just induction doing the work.

Watch this experiment

I spun up the three magnet rotor and let the main cap bank sit at 13 volts drawing about an amp. Once I shut off the supply the voltage started dropping but the RPMs did the opposite—they climbed. You can hear the transition in the video as it passes 1000 RPM and keeps accelerating. The little cap bank in the back was also getting topped off from the passing magnets.

What you'll learn

You'll see exactly how a three magnet system 120 setup behaves when the coil positive end has multiple things clipped to it. We'll look at why speed increases while cap voltage falls, what the Bedini does spike is doing, and how much capacitance seems to matter. All measurements straight from the bench—no theory, just what I observed.

From the bench

The coil is 1 and 1/2 lbs of 32 gauge wire. About a quarter of it sits underneath the wheel with the rest offset. The magnetic field reaches out so the whole coil still gets affected. I had the main cap bank, a small cap bank, and the power supply (turned off most of the time) all clipped to the positive end of the coil. The rotor uses three magnets spaced 120 degrees apart. I monitored speed by multiplying the meter reading by three—hit almost 1300 on the display which works out to around 3900 RPM.

How it works / what we changed

I charged the cap bank to 13 V at about 1 A then disconnected the supply. Voltage started dropping immediately but the rotor accelerated. The induction from the spinning magnets kept filling the caps and the higher the caps got, the faster the whole thing went. I jiggled the resistor once when a connection felt loose and it throttled right up. Even after dipping below 10 V the speed continued to climb. When I finally unclipped both grounds the little cap bank kept increasing from coasting induction.

Three magnet system 120

It's a three magnet system, 120°. The rotor isn't maglev so it won't reach astronomical speeds, but it still climbed steadily past 1000 RPM and approached 3900 total. The 120 degree spacing means the coil sees a pulse every third of a rotation. I multiply the meter reading by three to get true RPM. Even with only a quarter of the coil directly under the wheel the setup still produced strong induction because the field extends outward.

Coil positive end

The cap bank is clipped to the beginning of the coil, positive end of the coil. You got three things clipped to the positive end: the cap bank, the little cap bank, and the power supply. The Bedini does spike goes directly to the cap bank. In order for the energy to get to ground it has to go through the coil. I noticed that as long as there's enough capacitance the exact values can vary and the system stays forgiving.

Builder checklist

• 1.5 lb 32 gauge coil with proper offset under the rotor
• Three magnets spaced 120° on a balanced wheel
• Main cap bank and small cap bank both clipped to coil positive end
• Resistor in place and connections tight—jiggle test before final run
• Multimeter on the cap bank and RPM display set to multiply by three
• Ground disconnect ready for clean shutdown

Troubleshooting

If the speed drops off, check the connections at the coil positive end—mine needed a wiggle once and it throttled right up. When the meter shows 0 A it can be splash-back from the cap bank; watch the voltage trend instead. If the little cap bank isn't charging, make sure it's still seeing the spike even when the main supply is off. The system is forgiving but loose clips will kill the effect fast.

Safety

Keep fingers clear of the spinning rotor. Capacitors hold charge after you pull the plug so discharge them safely before touching. The coil can get warm at higher speeds. I unclip grounds to shut down instead of using a mechanical switch—works for me but do what feels safe on your bench.

FAQ

Why does speed increase when voltage is dropping? The induction as it goes faster fills those caps up, and the higher those caps are, the faster the whole thing goes. It's not coming from a power supply or battery.

Do I need exact capacitance values? The values can vary. This is very forgiving as long as you know what's what.

How do you calculate RPM on a three magnet system 120? Almost 1300 on the meter, then you divide by three? No—multiply the reading by three to get true RPM.

What is the Bedini does spike doing here? When the Bedini does spike, that spike goes directly to the cap bank clipped at the coil positive end.

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
• How to Maximize RPM on Your Pulse Motor
• Pulse Motor Rotor Design: Magnets, Materials and Balance

Watch this experiment on YouTube

• ▶ Watch full on YouTube