I Finally Got My Pulse Motor Running (Trigger Coil)

Hook

I finally got my pulse motor running smoothly with a trigger coil and even pushed a homemade reed switch to 345 volts. Here's what actually happened on the bench.

Watch this experiment

I spin up a two-magnet rotor past a 20-gauge 1500-turn coil wired as both trigger and drive. You can see the exact moment the magnet passes the center and the circuit kicks in. Later I swap to a homemade reed switch and get visible contact movement every time a magnet passes.

What you'll learn

You'll see how a trigger coil works in a real pulse motor, why parallel winding helps timing, what a homemade reed switch looks like in action, and how the K energy.store SSG circuit switches power. Plus the difference between motor side (spinning wheel) and generator side (lit bulb).

From the bench

On the bench today I've got a simple rotor with two magnets, a 20 gauge coil wound with 1500 turns, and the trigger coil wound right alongside it in parallel. The circuit is a K energy.store SSG generator circuit using a transistor to switch on and off. Input comes from the power supply, the spinning wheel is the motor part, and the light bulb shows the generator output. I turned the voltage down a bit before each run so I could catch the exact moment the magnet passes the center of the coil.

How it works / what we changed

A pulse motor is basically a motor and generator that runs on a binary on-off system. The trigger coil sits there and when the magnet passes the center it has enough magnetic strength because of the core to activate the trigger. That closes the circuit, forces energy through the rest of the coil, and pushes the rotor along its merry way. I wound the trigger coil in parallel with the drive coil so the timing is right on. I also tried a homemade reed switch — you can see the little piece move every time the magnet passes it and make contact. The cool thing is with enough coil in the system you can get tremendously high voltage through these switches. I used a little DC-to-DC transformer and it got up to 345 DC volts. When I removed the resistor the switch fused, so I learned that resistor is necessary at higher power.

magnet passes

Every time the magnet passes the center of the trigger coil the magnetic strength is enough to activate the trigger and close the circuit. You can see the same thing with the homemade reed switch — the magnet passes and the contact visibly moves and touches the other side. On the two-magnet rotor it happens twice per revolution and that's what keeps the pulse motor spinning. Timing is everything and the parallel-wound trigger coil makes the magnet passes line up almost perfectly with the drive pulse.

Builder checklist

• Wind trigger coil in parallel with drive coil for best timing
• Start with voltage turned down so you can see the magnet passes clearly
• Add a resistor when using reed or contact switches at higher voltage
• Use a two-magnet rotor with 20 gauge 1500-turn coil as a safe starting point
• Have both an input power indicator and a generator output bulb ready
• Position the switch or coil so the magnet passes at the right spot every time

Troubleshooting

If the rotor won't keep spinning, check that the magnet passes directly over the center of the trigger coil. When I removed the resistor the homemade reed switch fused and the circuit stopped working completely. If your timing feels off, try rewinding the trigger coil parallel with the drive coil. The light bulb output only lights when the wheel is spinning, so low speed means weak generator action.

Safety

High voltage can appear quickly once you add the transformer — I hit 345 DC volts. Always put the power through coils first before it reaches a reed switch or you risk fusing the contacts. Keep hands clear of the spinning rotor and watch for arcing when the switch closes.

FAQ

How does the trigger coil know when to fire?

When the magnet passes the center it induces enough voltage in the coil (thanks to the core) to turn on the transistor and close the circuit.

Can I use a regular reed switch instead of homemade?

Yes, but the video shows the homemade version so you can see the actual movement when the magnet passes.

Is this the same as a Bedini SSG?

It's built on the same SSG circuit but focused on the pulse motor action and trigger coil timing.

How much voltage can these switches handle?

With enough coil and a resistor I reached 345 DC volts, but without the resistor the switch fused immediately.

Do pulse motors really produce extra energy?

In my experience you get out what you put in minus losses, but you do get both mechanical spin and electrical output you can send to a cap bank or another motor.

Related on this site

• How to Build a Pulse Motor (Parts, Coil Placement & Circuit)
• What Is a Pulse Motor? How It Works (Beginner Explainer)
• Pulse Motors for Beginners: Start Here
• Bedini Motor & SSG Circuit Guide (Beginner Bedini Explained)
• Understanding Back EMF in Pulse Motors
• How to Wind Coils for a Pulse Motor (Step by Step)

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