By Papa Bale · April 5, 2026
If you've stumbled onto this page, you're probably asking the same question I asked a few years ago: what is a pulse motor, exactly? The term gets thrown around a lot in DIY electronics and alternative energy communities — sometimes accurately, sometimes not. Let me give you the clearest explanation I can, built on years of hands-on experimenting.
A pulse motor is an electric motor that runs on timed electrical pulses rather than continuous current. Instead of a constant flow of electricity through its coils, a pulse motor fires brief bursts of energy at precisely the right moment to push or pull permanent magnets on a spinning rotor. The result: rotation driven by electromagnetic attraction and repulsion, triggered in carefully timed intervals.
This is fundamentally different from a conventional DC motor, which draws continuous current. Pulse motors are often called "switched reluctance" or "pulsed electromagnetic" motors in engineering literature, but in the hobbyist world, the term "pulse motor" or "Bedini motor" covers most of these designs. Speaking of which — see the Pulse Motor vs Bedini Motor comparison to understand the nuance.
The concept of pulsed electromagnetic motors dates back to the earliest days of electrical experimentation in the 19th century. But the hobbyist revival is largely credited to John Bedini, an inventor who popularized specific circuit designs in the 1980s and 1990s. Bedini's work inspired thousands of experimenters to explore these motors for their efficiency characteristics and the fascinating back EMF (back electromotive force) they produce.
Papa Bale's journey started with childhood fascination — magnets at age 5 — then a 30-year gap before diving back in and building a YouTube channel around these experiments. The community has grown enormously since then.
Here's the pulse motor explained step by step:
The key to how a pulse motor works is that timing: fire too early or too late and you brake the motor instead of accelerating it. Get it right and the motor can run with remarkable efficiency.
Back EMF — back electromotive force — is one of the most interesting aspects of pulse motors. When the transistor cuts off the pulse, the magnetic field in the coil collapses rapidly. This collapse induces a reverse voltage spike, often much higher than the supply voltage. In a conventional motor circuit, this spike is simply dissipated as heat. But in a properly designed pulse motor circuit, it can be captured and used to charge a secondary battery.
This back EMF recovery is what makes pulse motors so fascinating to experimenters: the motor runs on one battery while partially charging another. It doesn't violate physics, but it does demonstrate that careful circuit design can dramatically improve system efficiency. Check my dedicated guide on Understanding Back EMF in Pulse Motors for the full breakdown.
So why do thousands of hobbyists build pulse motors? Several reasons:
Short answer: no. Longer answer: see my dedicated post on Pulse Motors and Free Energy: What's Actually Going On. The short version is that pulse motors are highly efficient machines, and the back EMF recovery can make the numbers look surprising — but they operate within the laws of thermodynamics. The fascination is real; the overclaims are not.
Understanding the individual components of a pulse motor helps clarify how the system works as a whole. Each part plays a critical role in the timing and efficiency of the motor:
The rotor is the spinning disc or wheel that carries permanent magnets past the stationary coil. Most pulse motor builders use neodymium magnets (N35 to N52 grade) because of their exceptional magnetic field strength relative to size. The magnets are typically arranged with all north poles facing outward (or all south poles) to ensure consistent triggering. A well-balanced rotor is essential — even slight imbalances cause vibration that wastes energy and stresses bearings.
The coil is the electromagnetic heart of the pulse motor. When energized, it creates a magnetic field that either attracts or repels the passing rotor magnets. Coil design involves tradeoffs: more turns increase inductance and back EMF voltage but also increase resistance; thicker wire (lower AWG) handles more current but takes up more space. See our wire gauge guide for detailed recommendations.
Timing is everything in a pulse motor. The trigger mechanism detects when a magnet is approaching the coil and fires the transistor at precisely the right moment. Options include:
The transistor acts as an electronically controlled switch, turning the coil current on and off thousands of times per minute. Common choices include the 2N3055 (classic, robust), TIP31C (budget-friendly), and TIP35C (higher power). The transistor must handle the peak current through the coil and withstand the back EMF voltage spikes. See our transistor selection guide for detailed comparisons.
While pulse motors are primarily experimental and educational devices, they have several practical and research applications:
Pulse motors are exceptional teaching tools for understanding electromagnetic induction, transistor switching, and energy recovery concepts. Students and hobbyists can see immediate visual feedback from circuit adjustments, making abstract electromagnetic principles tangible and intuitive.
The high-voltage pulses from back EMF recovery have been observed to have unique effects on lead-acid batteries. Some experimenters use pulse motor circuits specifically for battery desulfation and conditioning, reporting restored capacity in older batteries. While the mechanisms are debated, the practical results have been documented by many builders.
Pulse motors serve as platforms for researching switching efficiency, optimal timing algorithms, and energy recovery methods. The lessons learned from pulse motor optimization can inform the design of more efficient conventional motors and power electronics.
The high efficiency of well-tuned pulse motors makes them suitable for demonstrations running on minimal power — solar cells, small batteries, or even ambient energy harvesting. Their visual appeal (spinning magnets, flashing LEDs) makes them engaging display pieces.
Several variables determine how efficiently a pulse motor converts electrical input into mechanical rotation:
The most critical factor is the position of the coil relative to the rotor magnets when the pulse fires. Fire too early and the coil brakes the magnet; fire too late and you miss the optimal push. The ideal firing point is just as the magnet approaches the coil center — the "sweet spot" that requires careful adjustment to find.
The gap between the coil face and the passing magnets affects magnetic coupling strength. Smaller gaps (2-4mm) provide stronger interaction but risk mechanical contact; larger gaps reduce efficiency. Finding the optimal gap is part of the tuning process.
How quickly the transistor turns on and off affects both the sharpness of the magnetic pulse and the magnitude of the back EMF spike. Faster switching (using MOSFETs instead of BJTs, for example) can improve efficiency in advanced builds.
Since pulse motors operate with minimal continuous power, bearing friction represents a significant loss. Quality bearings (skateboard 608 bearings are popular) and proper balance are essential for good performance.
If you're now itching to actually build a pulse motor, start with my Complete Beginner's Guide or the broader Pulse Motors for Beginners overview. If you're completely new, those two posts are your on-ramp into the hobby.
A pulse motor works by firing brief bursts of electricity through a coil at precisely timed intervals. When a magnet on the spinning rotor approaches the coil, the coil energizes and either attracts or repels the magnet, giving it a push. The coil then turns off, allowing the rotor to coast until the next magnet arrives. This pulsed operation is fundamentally different from conventional motors that use continuous current.
The key difference is that pulse motors use timed pulses of current rather than continuous flow. Conventional DC motors draw steady current and use mechanical commutators or electronic controllers to maintain rotation. Pulse motors energize the coil only briefly when the rotor magnet is in the optimal position, then turn completely off between pulses. This allows pulse motors to capture and reuse back EMF energy that conventional motors waste as heat.
No, a pulse motor cannot run forever. While well-designed pulse motors can be highly efficient and recover some energy through back EMF, they still require an energy input to overcome friction, resistance losses, and air resistance. Claims of "free energy" or perpetual motion violate the laws of thermodynamics. However, pulse motors can run for extended periods on minimal power and demonstrate fascinating efficiency principles.
Back EMF (back electromotive force) is a voltage spike generated when the magnetic field in a coil collapses — which happens every time the transistor turns off. In conventional motors, this energy is wasted as heat. In pulse motors, a recovery circuit can capture this spike and use it to charge a secondary battery. This recovery is what makes pulse motors interesting for efficiency research and battery charging applications.
A basic pulse motor can be built for $20-50 using common electronic components. The main costs are magnet wire ($5-15), neodymium magnets ($5-15), a transistor ($1-3), and a rotor disc (often free if using scrap wood or PVC). More advanced builds with multiple coils or precision components may cost $50-100. Compared to commercial motor kits, DIY pulse motors are very affordable.
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