What is a permanent magnet generator?

A permanent magnet generator produces electricity using fixed magnets rather than electromagnets that must first be energised. Because the magnetic field is always present, the machine generates from the very first rotation and needs no excitation current, no slip rings and no external power to get started.

TESUP's generator is a 24-pole permanent magnet machine using NdFeB N42 (neodymium-iron-boron) magnets, each 60 × 25 × 5 mm, nickel-coated and bread-shaped. There are 24 of them, 180 cm³ of magnet in total, turning inside a stator measuring 16 cm × 12 cm.

Why 24 poles, and why no gearbox?

Pole count sets the relationship between rotational speed and output frequency. A generator with few poles has to spin fast to be useful, which is why many turbines put a gearbox between the rotor and the generator. A gearbox is also the component most likely to fail, the one that needs oil changes, and the one that makes noise.

Twenty-four poles produce usable voltage at low rotational speed, so the rotor can drive the generator directly. No gearbox means no gear oil, no gear wear, and one fewer thing that can seize on a roof in February.

What is cogging torque?

Cogging torque is the resistance you feel when you turn a permanent magnet motor by hand — that notchy, step-by-step reluctance, as though the shaft wants to settle into fixed positions. It is caused by the magnets attracting toward the steel teeth of the stator. Each tooth is a preferred parking spot, and the rotor has to be pushed out of it.

In a fan or a power tool, cogging is a minor annoyance. In a small wind turbine it is the single most important obstacle to low-wind performance, because cogging torque is a fixed threshold that the wind must overcome before anything turns at all. Below it, output is not small — it is zero.

This is why cut-in wind speed matters so much more than rated power for a domestic turbine. Rated power describes a windy day. Cut-in speed describes every other day.

How does skewing the magnets reduce cogging torque?

If every magnet sits exactly parallel to the stator teeth, all 24 poles reach their attraction peak at the same instant. Those peaks add together, and the result is a strong, notchy pulse the wind has to break through on every step.

Skewing means mounting the magnets at a slight angle to the axis of rotation, so that each magnet engages a stator tooth progressively rather than all at once. The peaks no longer coincide — they spread out and partially cancel. The total torque the generator produces is unchanged; what disappears is the ripple.

TESUP uses skewed magnet mounting for exactly this reason. Lower cogging torque means a lower breakaway threshold, and a lower breakaway threshold is what allows the Atlas to self-start at 2 m/s with its low-wind blade set — roughly one third the cut-in speed of a typical horizontal-axis turbine.

Skewing is not free: it slightly reduces peak flux linkage, so a skewed machine gives up a little top-end output in exchange for starting earlier. For a domestic turbine, where light wind is the common condition and storms are rare, that is the right trade to make.

Why does a turbine that makes about 1 kW use a 15 kW motor?

Because a generator's rating is a thermal limit, not a promise of output. The 15 kW continuous rating is what the machine can sustain indefinitely without overheating, and it is set by three things: the Class 200 °C enamelled wire insulation (IEC 60317-13 GR 2, the same grade used in industrial servomotors and EV drivetrains), the 4 kg of copper winding acting as thermal mass, and passive cooling through the housing.

At the Atlas's typical output of around 1 kW, the motor is running at under 7% of its continuous rating. It runs cold. Copper losses rise with the square of current, so a machine operating far below its limit wastes very little as heat — and heat is what ages insulation and eventually ends a motor's life.

The 22 kW peak figure is the short-term overload capacity for gusts. It is bounded by two physical limits: the demagnetisation threshold of the N42 magnets, and saturation of the stator iron.

Why tooling is what actually decides cogging torque

Skewing only cancels cogging torque if every magnet sits exactly where the design says it should. The cancellation is a geometric effect: 24 magnets, each offset by a precise angle, so their attraction peaks fall out of step with one another. If the seats those magnets sit in vary from one rotor to the next, the skew angle varies with them — the peaks drift back into alignment, cogging rises, and the wind speed needed to break the rotor free rises with it.

That is why ±0.05 mm across all machined components is not a boast on a spec sheet. It is the tolerance the physics requires. A rotor built to loose tolerances can carry exactly the same magnets, the same pole count and the same copper, and still start later in the wind.

Holding that tolerance on one prototype is straightforward. Holding it on every unit, for years, is a tooling problem — which is why this arrived at our facility:

A press tool like this is not bought for speed, though it is faster. It is bought for repeatability. The first rotor formed on it and the ten-thousandth come out of the same steel, located by the same pillars, to the same dimensions. That is the only way a tolerance figure means anything once you are building at volume rather than one at a time.

It also means one more component that no longer depends on somebody else's quality control. Our European facilities already produce over 270 components in-house — generators, electronic cards, blades and mounting hardware. Every tool that lands makes that list one item longer.

Where the energy actually comes from

The power available in wind follows:

P = ½ · ρ · A · V³ · C_p · η

Where ρ is air density, A is swept area, V is wind speed, C_p is the power coefficient and η is electrical efficiency. The Atlas rotor sweeps 1.035 m² (1030 mm diameter × 1005 mm height), reaches a C_p of 0.28 in good wind, and converts at 92% electrical efficiency.

The term that dominates is V³. Wind speed is cubed, so a site with 30% more wind yields roughly double the energy, not 30% more. This is why mast height and siting change results more than any specification on this page — and why an honest answer to "how much will I get?" always begins with a question about your location rather than a number.

Full generator specification

What this does and does not tell you

Every figure above is a property of the machine, and machine properties are the part we control. Cogging torque, pole count, magnet grade, insulation class and machining tolerance are the same in every unit we ship.

Annual energy yield is not. That depends on your wind, and published yield for the Atlas spans 180–2,900 kWh per year precisely because the range between a sheltered suburban garden and an exposed coastal site is that wide. Tell us your location and mast height and we will give you a realistic range rather than a best case.

See the Atlas specification →

One owner in Brazil, one Atlas on a 10-metre mast, and a month that ended on a round number: one megawatt-hour. No battery, no second turbine, nothing exotic — just a vertical-axis Atlas wired straight to the grid through a hybrid inverter.

What he actually has

• A new Atlas vertical-axis turbine — the 1.03 m × 1.00 m rotor.
• Low-Wind blade set — the set built to start turning at 2 m/s.
• A 10-metre mast, clear of the roofline.
• A hybrid inverter, grid-tied, no battery — everything generated goes straight into the house or back out to the grid.

The figure is the owner's own reading, taken from the wind channel of his hybrid inverter over one month. We are publishing it as he reported it.

So what is a megawatt-hour, really?

A thousand kilowatt-hours is an abstraction until you spend it. Here is what that month would cover:

How long would 1 MWh run your home?

It depends entirely on where you live — a home in Ireland gets through electricity roughly twice as fast as one in Brazil. Same megawatt-hour, very different number of months:

Based on typical national household electricity averages. Your own consumption is the number that matters.

Why this site did it

Wind is not democratic. Power in the wind rises with the cube of wind speed, so a site with 30% more wind does not give you 30% more energy — it gives you roughly double. That is why the same turbine can be quietly brilliant in one garden and merely useful in the next one along.

Three things were working in this owner's favour:

• Height. Ten metres puts the rotor above the turbulent, slowed air that sits near buildings and trees. It is the cheapest performance upgrade in wind.
• The right blades. The Low-Wind set trades top-end survivability for early starting — it is turning while other rotors are still standing still.
• No battery in the way. Grid-tied means nothing is ever curtailed because a battery happened to be full. Every kilowatt-hour has somewhere to go.

What to expect at your own address

Be honest with yourself about your wind before you buy. Ten metres of clear air and a coastal or open-country site is a different proposition from a sheltered suburban garden, and the cube law means the gap is bigger than it looks. If you tell us your location and mast height, we will give you a realistic range rather than a best case.

See the Atlas →

There is a particular moment in manufacturing that never stops being satisfying: the moment the shrink-wrap goes on, the forklift lifts, and a week of work disappears into a truck.

This week that truck is heading for the Netherlands.

As the world's biggest manufacturer of household wind turbines and flexible solar panels, we ship to customers in dozens of countries — but the Netherlands has always held a special place. It is one of our largest communities of home energy producers, and it's easy to see why: a country that reclaimed its land from the sea, built its golden age on windmills, and now leads Europe in rooftop solar was never going to need convincing that the wind and the sun are worth harvesting.

Inside these boxes: Atlas and Magnum wind turbines, flexible solar panels, mounting poles and charge controllers — each one built, tested and packed by our team, each one carrying the little QR label that will one day let its owner register it and watch it generate.

Delivery is free, as it is for every TESUP customer. In a few days these pallets will be unwrapped in Dutch gardens, on Dutch rooftops and beside Dutch canals — and a few weeks after that, they'll be quietly making electricity out of North Sea wind.

To everyone waiting on this shipment: it's on its way. To everyone thinking about joining them: the next truck is already being loaded.

The south-west coast is one of the windiest parts of Britain, and very little of that wind is polite. It comes off the Atlantic carrying salt, it arrives in gusts rather than steady streams, and it does not stop for the winter holidays. It is a good place to generate electricity and a hard place to put a machine.

In February 2023, a further-education college put a Magnum up in it.

We can be precise about the date, because it is stamped into the machine. The build date sits in the middle of the serial number on the control box: the twenty-seventh of February, 2023. The installation is a straightforward one — the turbine, a charge controller, a mounting pole, an inverter and a battery to hold what the wind delivers at three in the morning when the campus is empty.

Three years and five months later, we heard from the college’s installer. They needed a replacement turbine.

Not because it had failed. Because somebody had vandalised it.

Why that’s the interesting part

Every manufacturer will tell you their equipment is durable. What none of us can do honestly is tell you how a machine behaves in year three, because most of the case studies you read were written in month two, when everything is new and the photographs are clean.

This one wasn’t. A college campus is an unusually unsentimental test. Nobody is watching the output every morning the way an enthusiast at home does. Nobody nurses it. It runs unattended through term time and through the summer, in coastal air, and it is expected to simply be there. For three and a half years, it was — right up until the moment it met something a turbine is not designed to survive, which is a person with intent.

The rest of the system says something too. The inverter, the battery and the charge controller are all still in place, all still working, and none of them are being replaced. The college is buying one part. That is what a well-matched system looks like after three years: when one component goes, you replace one component.

What we’d tell anyone siting a turbine somewhere public

We are not going to pretend we have a vandal-proof product. Nobody does. But this is the second thing worth taking from this installation, and it is more useful than the first:

• Height is the cheapest security you can buy. A turbine that cannot be reached from the ground cannot be reached casually. Most vandalism is opportunistic rather than determined.
• Put the electronics where the people aren’t. At this site the control box and inverter are in a cabinet — which is exactly why the college is replacing a turbine rather than a whole system.
• Cover it with whatever camera you already have. Sites like colleges almost always have CCTV somewhere. Pointing an existing camera at the mast costs nothing.
• Tell your insurer it’s there. Vandalism is very often covered. It is much less often claimed for, because nobody thought to list the turbine.

The replacement

The Magnum is still in the range, still in stock, and still designed to bolt onto the same mounting pole. The college will be turning again shortly — on the same mast, into the same battery, in the same coastal wind.

We would rather have written this story in a few more years, and about a turbine that finally stopped on its own. We’ll take this one.

In stock in New Jersey

For years, every TESUP was hand-built in our European factories and shipped across the Atlantic to each customer one by one — beautiful engineering, but a long wait. Not anymore. We now keep stock in New Jersey. When you order, it ships domestically from our US warehouse and usually arrives at your door in about a week — with free USPS delivery and duties already handled. No customs surprises, no month-long waits.

New, lower US prices

Shipping in bulk to our own warehouse cut our costs — and we’ve passed that saving straight on to you:

Still built in Europe

Nothing about the quality has changed. Every unit is still designed and hand-assembled in our European factories and serial-tested before it’s dispatched. You’re getting the exact same TESUP — we’ve simply moved it closer to you. Made in Europe, stocked in America.

Shop the US store →

Some technology hides in a cupboard. This one you'll want on show. Sleek, frameless and just 1.49 mm thin, the TESUP Flexible Solar Panel is as beautiful as it is clever.

Look at how it lies — following the ground, catching the light, a single elegant sheet of monocrystalline cells. No bulky aluminium frame. No heavy glass. Just clean, quiet power that goes where ordinary panels can't.

Made to fit anywhere

That flexibility isn't just for looks. It's what lets one panel serve a home, a boat, a campervan or a garden studio. Fix it with the pre-applied adhesive backing, or thread hooks, screws or zip-ties through the corner eyelets — and it's ready.

230 watts of quiet beauty

Behind the good looks is serious performance: high-efficiency monocrystalline cells delivering 230 W per panel, wrapped in a self-cleaning, anti-reflective ETFE skin that stays clear year after year. It's engineering you can actually enjoy looking at.

Solar that suits your space

Whether it curves across a motorhome roof, lies flat on a shed, leans against a sunny wall or catches the light on a balcony, the TESUP Flexible Solar Panel proves that clean energy doesn't have to be an eyesore. Sometimes, it can be the most beautiful thing in the garden.

Discover the Flexible Solar Panel →

Photo: a TESUP customer's own installation. Already have TESUP solar? Explore accessories at our spare-parts store.

Confession: this week, the most excited person in our warehouse wasn't celebrating a sale. They were celebrating a new tool. 😄

Because at TESUP, we get a little obsessed with the details — even the ones you never see. Take a look:

Small tool, big difference

That satisfying ka-chunk is our newest addition: a pneumatic box-sealer that closes every TESUP carton fast, tight and perfectly square. It might not be as glamorous as a spinning turbine — but it's part of the same promise.

Why the box matters

Every TESUP turbine is hand-assembled, serial-number tested — and then it sets off on a journey that can cross oceans and continents to reach one of 70+ countries. A beautifully built turbine deserves packaging that protects it every mile of the way. So yes, we get excited about a better box-sealer. It means fewer bumps, tidier deliveries, and your turbine arriving exactly as it left our hands.

And look closely at the carton itself: the flag, the line “We are changing the game. You are changing the world.” Even the box is part of the story.

The little things add up

New toys, better tools, tidier boxes — none of it makes headlines. But it's exactly this kind of quiet, everyday care that turns a good product into one you can rely on for a decade. That's the TESUP way.

Discover the Atlas Wind Turbine →

Already running a TESUP? Every part is available at our spare-parts store.

The world's supply chains have rarely been this turbulent. Trade wars and tariffs redraw the map every month. And the rare-earth minerals that modern technology depends on have become some of the most fought-over materials on Earth.

And yet — week after week, more TESUP turbines leave our facility than the week before.

The rare-earth reality

Here's something most people never think about when they picture a wind turbine: the magnets inside its generator are made from rare-earth elements like neodymium. They're what turn spinning blades into clean electricity — and today they sit at the centre of a global tug-of-war over supply, export controls and price. For anyone who builds real energy hardware, this is the defining challenge of the decade.

Our answer is control

When the world outside is unpredictable, you protect what you can hold in your own hands. That's why TESUP builds the way it does: hand-assembled in our own facility, every unit given its own serial number, every turbine video-tested before it's allowed near a truck. We don't scatter the important work across anonymous suppliers — we keep it close, where we can guarantee it. When a supply chain wobbles, control is what keeps promises intact.

Getting stronger, not smaller

Plenty of companies met the last few years by shrinking — thinner products, quiet cost-cutting, quality that slips where they hope you won't look. We went the other way. We reinforced our blades, widened our spare-parts range, extended support to every unit we've ever sold, and kept our warranty at a full two years. Every loaded truck that pulls away from our doors is proof: against the headwinds, TESUP is growing.

What it means for you

Resilience isn't an abstract idea — it's the reason your turbine, your warranty and your spare parts are backed by a company built to endure. When you choose TESUP, you're not just buying clean energy. You're backing a maker that gets stronger precisely when it's hardest to.

Discover the Atlas Wind Turbine →

Already running a TESUP? Every part is available at our spare-parts store.

Passion doesn't switch off when the final whistle blows — and neither does energy. At TESUP we believe a champion's energy is made at home: with sunshine by day and wind that never stops blowing.

Celebrate with energy of your own: Discover the Atlas Vertical Wind Turbine →

Images: Adobe Stock (licensed) & TESUP.

The turbine was turning anyway.

Video: Helimariner on YouTube — shared with our thanks.

Six years and 35,000 views later, that quiet clip is still one of our favourite pieces of proof. Not a studio shoot, not a render — a real roof, a real satellite dish in the corner of the frame, and a vertical-axis turbine doing exactly what it was designed to do: wake up in wind that leaves conventional turbines standing still.

What we love most is his honesty. In his own words: “You must have a continuous flow of strong wind in order to produce power.” He is right — a light breeze starts the blades; steady wind is what fills the batteries. That is why he runs his Atlas alongside his solar panels: sun by day, wind whenever it blows, one hybrid system that never fully sleeps.

Six years of weather later, his Atlas is still up there. If yours has been spinning that long too, our spare-parts store will keep it going for six more.

Discover the Atlas Vertical Wind Turbine →