Everything you want to know about pulse motors, Bedini SSG circuits, back EMF, and DIY motor building — answered by Papa Bale.
A pulse motor is an electric motor driven by timed electrical pulses rather than continuous current. Brief bursts of electricity through a coil attract or repel permanent magnets on a spinning rotor, creating rotation. They're popular with DIY experimenters for their educational value, efficiency characteristics, and fascinating back EMF recovery capabilities. Full explainer →
A trigger sensor (Hall effect sensor, reed switch, or feedback coil) detects when a rotor magnet is approaching a coil. This triggers a transistor, which fires a brief pulse of current through the coil. The energized coil attracts the magnet, accelerating the rotor. The pulse cuts off, allowing the rotor to coast until the next magnet arrives. Precise timing is the key to efficient operation — fire too early or late and the coil brakes instead of accelerates the rotor.
Not exactly. A Bedini motor is a specific, famous type of pulse motor designed by inventor John Bedini, using a bifilar coil where one winding drives the motor and one provides the trigger signal. All Bedini motors are pulse motors, but not all pulse motors are Bedini motors. The term "pulse motor" is broader and covers Hall-sensor-triggered designs, switched reluctance motors, and many custom configurations. Full comparison →
Yes! Pulse motors with back EMF recovery circuits can charge a secondary battery while running. The collapsing magnetic field when the transistor switches off produces a high-voltage spike. A recovery diode routes this spike to a secondary battery, gradually charging it. The primary battery runs the motor; the secondary captures the recovered energy. This is a real efficiency improvement, not magic — but it doesn't create energy from nothing. BEMF recovery guide →
Back EMF (back electromotive force) is a reverse voltage spike produced when current through a coil is suddenly cut off. The collapsing magnetic field induces a voltage — often many times higher than the supply voltage. Without protection, it destroys transistors. With a recovery circuit, this energy can be captured and stored rather than wasted as heat, improving overall system efficiency significantly. Understanding back EMF is central to building efficient pulse motors. Full BEMF guide →
A basic pulse motor build costs $20–$60 depending on what you already have. Neodymium magnets: $5–15. Transistor and resistors: $2–5. Magnet wire: $5–15. Rotor material: $0–20 (wood or PVC). 12V battery: $15–40. Papa Bale has demonstrated budget builds under $30 using 16AWG coil wire and accessible materials. You don't need expensive equipment to get started.
Magnet wire (enamel-coated copper wire) is the standard. Wire gauge matters: 16AWG is thick, easy to wind, and good for high-current builds — Papa Bale's popular 16AWG video demonstrates this well. 20AWG is a versatile middle ground for most 12V builds. 22AWG allows more turns, increasing inductance and back EMF spike voltage. For a first build, 20AWG is the safest recommendation. Full AWG guide →
Free energy (overunity) doesn't exist — pulse motors cannot produce more energy than they consume, full stop. What makes them interesting is efficiency: back EMF recovery captures energy that conventional circuits waste. Battery voltage readings can be misleading due to surface charge effects, which is why overunity claims persist. With careful measurement accounting for all losses (transistor heat, coil resistance, friction), total input always exceeds output. The hobby is genuinely educational — the overclaims are not necessary to justify building them. Full honest take →
Papa Bale is a self-taught DIY experimenter and YouTube content creator focused on pulse motors, Bedini motors, and magnetic induction. He fell in love with magnets at age 5, took a 30-year break, then returned to build one of the most authentic pulse motor channels on YouTube. His channel at @MPHJR documents real experiments — wins, failures, and everything in between — with no gatekeeping and a genuine passion for the science.
All videos are on YouTube at https://www.youtube.com/@MPHJR. The channel covers DIY pulse motor builds, Bedini SSG experiments, back EMF demonstrations, budget builds, and beginner tutorials. Written companion guides are available in the blog section of this site, and video breakdowns are in the videos section.
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Two great options: (1) Hall-sensor-triggered pulse motor — simple circuit, easy to understand, great for learning fundamentals; (2) Bedini SSG — proven, community-tested with extensive documentation and forum support. For complete electronics beginners, the Hall sensor design is simpler. For those wanting the deepest community resources, the Bedini SSG wins. Either can be built in a weekend for under $50. Beginners guide →
Popular choices: 2N3055 (classic Bedini SSG pick, robust, 15A), TIP31C (cheap beginner option, 3A, TO-220), TIP35C (serious builds, 25A), IRFP250N MOSFET (advanced, fastest switching). Papa Bale recommends TIP31C for a first experiment and 2N3055 for Bedini SSG builds. Always use a heatsink. Full transistor guide →
The Bedini SSG (Simple School Girl) is a specific pulse motor circuit by inventor John Bedini. It uses a bifilar wound coil — one winding drives the motor, one triggers it. A single NPN transistor switches the drive current. Back EMF spikes are recovered through a diode into a secondary battery. The circuit is self-triggering with no external sensor needed. It's the most documented and community-supported pulse motor design in existence. Full Bedini SSG guide →
Bifilar winding means winding two wires simultaneously on the same coil former, side by side. The two resulting coils have very tight magnetic coupling. In a Bedini SSG, one wire is the power/drive coil and the other is the trigger/feedback coil. To wind bifilar: tape two reels of wire together, secure both ends to the former, and wind them simultaneously as if they were one thick wire. Mark which end belongs to which wire before you start. Full coil winding guide →
Even numbers work best: 4, 6, 8, or 12. Eight magnets is the most popular choice — it provides smooth rotation with good momentum between pulses. More magnets mean smoother rotation but less coast momentum. All magnets must face outward with the same pole (all north or all south). Spacing must be perfectly even, or timing problems will fight you no matter how well you tune the coil. Full rotor design guide →
Lower AWG number = thicker wire. 16AWG: low resistance, handles high current, easy to wind, but fewer turns per coil and lower inductance. 22AWG: higher resistance, allows more turns, produces higher inductance and bigger back EMF spikes, better for efficiency-focused builds. For a first build, 20AWG is the best middle ground. Papa Bale's famous budget build used 16AWG for raw magnetic punch. Full AWG guide →
Yes! Papa Bale has a popular video showing a no-solder pulse motor build using clip leads and a breadboard. It's perfect for beginners who haven't yet learned soldering. Solderless builds are less reliable long-term and have slightly higher contact resistance, but are completely adequate for learning. Watch the build on YouTube at @MPHJR.
The rotor must be non-magnetic: MDF, plywood, PVC, acrylic, polycarbonate, or 3D-printed plastic. Metal rotors interact with the coil field unpredictably. Bicycle wheels are a popular ready-made option. Mount neodymium disc magnets (N35 or N42) with epoxy. Use low-friction bearings (skateboard bearings work great) and balance the rotor carefully — even slight imbalance wastes energy and stresses bearings. Full rotor guide →
Key improvements: (1) Add BEMF recovery circuit; (2) Optimize coil timing — trigger just before magnet reaches coil center; (3) Minimize air gap; (4) Use a faster transistor; (5) Use higher-inductance coil (more turns); (6) Balance rotor perfectly; (7) Use low-friction bearings; (8) Match coil resistance to supply voltage. Each improvement has measurable results. The optimization never ends — that's part of what makes the hobby so engaging.
Papa Bale's Pulse Motors at @MPHJR is one of the most authentic and educational pulse motor channels. Papa Bale documents real hands-on builds — DIY pulse motors, Bedini SSG circuits, back EMF recovery, budget builds, and beginner tutorials. Known for honest, no-gatekeeping content. Subscribe to watch real experiments, not theory. The companion website at papabalespulsemotors.com has written guides for every topic.
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