An electric car's motor turns the wheels using a magnetic field created by battery current, with no combustion, no crankshaft and no gearbox. Three technologies power the cars sold in Belgium. The difference between them barely touches your budget. The motor's power, on the other hand, can cost you more than €1,000 in tax in Wallonia.
How does an electric car motor work?
An electric traction motor is a machine that converts electrical energy into rotation through magnetic force. Two parts are enough to describe it: the stator, the fixed ring wound with copper coils, and the rotor, the part spinning in the middle that drives the shaft.
The battery stores direct current. The motor needs three-phase alternating current. In between sits the inverter, a power-electronics box that chops the battery current thousands of times a second to feed the stator coils one after another. That sequence creates a rotating magnetic field, and the rotor follows it. When you press the accelerator you are not metering fuel: you are asking the inverter to spin that field faster and harder.
The same motor works in reverse. Lift off, and the wheels drive the rotor, the machine becomes a generator and sends current back to the battery. That is the principle behind regenerative braking, and it is why an electric car uses less energy in town than on the motorway, the opposite of a petrol car.
Efficiency explains the rest. The US Department of Energy, on its fueleconomy.gov site, estimates that an electric car delivers more than 77% of the energy drawn from the grid to the wheels when recovered braking is counted, against 12 to 30% of the energy in the fuel for a petrol car. The motor alone exceeds 90% efficiency over a wide speed range; the losses sit mainly in the inverter, the battery and heat.
Three families of motors
Permanent-magnet synchronous, wound-rotor synchronous, asynchronous: all three share the same stator and differ in how the rotor becomes magnetic.
| Type | Rotor | Rare earths | Strength | Weakness | Examples sold in Belgium |
|---|---|---|---|---|---|
| Permanent-magnet synchronous | Neodymium magnets | Yes | Efficiency in town and at medium speed | Cost and dependence on magnets | Kia EV3, Volkswagen ID.4 (rear), Tesla Model Y (rear) |
| Wound-rotor synchronous | Coil fed with current | No | Good efficiency at high speed, no magnets | Some energy needed to excite the rotor | Renault 5 E-Tech, BMW iX3 Neue Klasse (rear) |
| Asynchronous (induction) | Copper or aluminium cage | No | Robust, cheap, no drag when idle | Higher losses at part load | Front motor of the Model Y, ID.4 4MOTION, iX3 50 xDrive |
The permanent-magnet motor dominates because it offers the best compromise on a mixed journey. Its rotor carries neodymium magnets, permanently magnetised, which lock onto the stator field without being fed any energy. Hyundai, Kia, Volkswagen and Tesla use it on their main axle. Its Achilles heel fits in two words: rare earths.
The wound-rotor synchronous motor replaces the magnets with a copper coil fed with current. Renault chose it from the Zoe onwards and kept it on the Mégane E-Tech and then the Renault 5 E-Tech, in 70, 90 or 110 kW versions. BMW has used it since its fifth drive generation, and the iX3 Neue Klasse launched in 2025 carries a revised version on the rear axle: BMW claims energy losses 40% lower than the previous generation across the whole drivetrain.
The asynchronous motor is the oldest and simplest. Its rotor carries neither magnet nor power supply: the stator field induces a current in it, hence its other name, induction motor. It has one drawback, poorer efficiency when working at light load. And one precious quality: switched off, it drags on nothing. Hence its current role as the helper motor on the front axle of all-wheel-drive versions. The Tesla owner's manual describes exactly this layout on the Model Y: permanent magnets at the rear, induction at the front. Volkswagen does the same on the ID.4 Pro 4MOTION, BMW on the iX3 50 xDrive.
Does an electric car have a gearbox?
No. A single-speed reduction gear, a few cogs that gear down the motor's rotation, is enough to link the motor to the wheels.
Two reasons. An electric motor delivers its maximum torque from the very first revolution, whereas a petrol engine has to rev up before it pulls; it therefore needs no short gear to move off. And it spins much faster, beyond 15,000 rpm on most recent models against 6,000 to 7,000 for a production petrol engine, which covers the whole 0 to 180 km/h range without changing gear.
Your D, N, R selector only sends an order to the inverter. Reverse? The motor simply turns the other way.
The exception proves the rule. From 2019 the Porsche Taycan got a two-speed gearbox on the rear axle, a short first gear for standing starts and a long second gear for efficiency at high speed. For the 2027 model year, Porsche announces an E-Shift mode that simulates eight gears, jolts and sound included, without adding a single cog. That is feel, not mechanics.
No production electric car has a manual gearbox. A licence restricted to automatic transmission is therefore enough to drive any of them.
Does the motor type change your consumption?
A little, and mainly on the motorway. This is the serious objection to my argument, and it deserves a straight look.
On paper, each technology has its comfort zone. The permanent magnet excels at medium revs, those of town and main roads. At high speed its field has to be artificially weakened, which costs energy, and that is where the wound rotor, whose current can be adjusted at will, takes back the advantage. The induction motor loses ground at part load, hence its role as a helper. An engineer could draw you the three efficiency maps and they would all be different.
But a car's real-world consumption depends first on its weight, aerodynamics, tyres and the quality of its software. The Renault 5 E-Tech, without magnets, and the Kia EV3, with magnets, both rank among the most frugal in their segment. Published tests do not isolate the motor's share in the gap between two models, and I have found no serious source that does.
So I would never buy a car for its motor type. I would compare its measured motorway consumption, the figure we record on our model pages.
One argument does hold, on ethics and geopolitics. Rare-earth refining is heavily concentrated in China, and a magnet-free motor shields the car from an embargo or a price spike. If that matters to you, Renault and BMW have an answer, and Tesla and Volkswagen do not yet have one on their main motor.
Power in kW, a tax line in Wallonia
At the dealership they talk horsepower and acceleration. Never tax. Yet in Wallonia, the motor's kilowatts set your TMC (taxe de mise en circulation, the one-off registration tax).
The Walloon formula multiplies a base amount tied to power, the maximum authorised weight and an energy coefficient that rises in steps: 0.01 up to 120 kW, 0.10 from 121 to 155 kW, 0.18 from 156 to 249 kW, 0.26 beyond. In Flanders, power has not counted at all since 1 January 2026: the Flemish Region charges €61.50 of registration tax and a flat annual road tax of €107.16, indexed every 1 July, on any electric car registered since that date. In Brussels, every electric car pays the minimum tax, €78.88 according to Moniteur Automobile for the period from 1 July 2026 to 30 June 2027.
| Car | Motor(s) | Power | TMC Wallonia | TMC Flanders | TMC Brussels |
|---|---|---|---|---|---|
| Renault 5 E-Tech 150 hp | Synchronous, wound rotor | 110 kW | €50 | €61.50 | €78.88 |
| Kia EV3 81.4 kWh | Synchronous, magnets | 150 kW | €283 to €310 | €61.50 | €78.88 |
| Volkswagen ID.4 Pro | Synchronous, magnets | 210 kW | €1,117 to €1,214 | €61.50 | €78.88 |
| Volkswagen ID.4 Pro 4MOTION | Magnets rear, induction front | 220 kW | €1,117 to €1,214 | €61.50 | €78.88 |
| BMW iX3 50 xDrive | Wound rotor rear, induction front | 345 kW | €1,753 to €1,893 | €61.50 | €78.88 |
Wallonia: order of magnitude calculated on the SPW Finances 2025-2026 scale with the weight range used in our registration tax article; the exact amount depends on your version's weight (field F.1 of the registration certificate) and on the 1 July indexation. Flanders checked on vlaanderen.be on 5 November 2026. Brussels according to Moniteur Automobile, to be confirmed on MyTax. Power figures from manufacturer data sheets. Our own calculation.
The table says one simple thing. Between a Renault 5 and an iX3 50 xDrive registered in Namur, the tax gap exceeds €1,700, for a difference that comes down to kilowatts alone. The same iX3 registered in Ghent pays €61.50.
Within a single range, the 155 kW boundary is worth watching. Going from 150 to 160 kW at equal weight lifts the Walloon tax from around €300 to more than €1,100. For a family torn between two versions, those €800 are worth an options pack.
One last point, because the question comes up at the counter: an electric car has no engine displacement, so no fiscal horsepower in the traditional sense. The kW figure on the data sheet is the one the Walloon tax office reads, and you convert it into horsepower by multiplying by 1.36.
How many kW does a family car need?
Less than you think. With 150 kW, the Kia EV3 81.4 kWh does 0 to 100 km/h in 7.7 seconds according to its data sheet, quicker than most of the compact diesels it replaces. With two children, the dog and a full boot on the E411 climb towards Namur, I have never lacked pull above 110 kW. Beyond 155 kW, in Wallonia, you are mostly paying for fun.
Four myths about the electric motor
- "An electric motor wears out like a combustion engine." It has no pistons, valves or timing gear; wear parts come down to bearings and seals, and most manufacturers warrant the drivetrain like the rest of the car.
- "More kW means more consumption." Not necessarily: at steady speed the car only asks for the power needed to overcome air and rolling resistance, whether the motor makes 110 or 345 kW. The extra weight of the powerful version, however, is paid for.
- "In-wheel motors are just around the corner." They remain confined to prototypes and small series; none of the cars in this table uses one, because a motor inside the wheel adds unsprung weight and suffers from impacts and water.
- "Two motors mean twice the servicing." The second motor, often an induction unit, has no more wear parts than the first, and servicing an electric car remains cheaper than a combustion car in Belgium.
Frequently asked questions
Does an electric car have a gearbox?
No, in the vast majority of cases. A single-speed reduction gear links the motor to the wheels, and the D, N, R selector simply tells the motor which way to turn. The exceptions can be counted on one hand: the Porsche Taycan has had two gears on its rear axle since 2019, and Porsche announces an E-Shift mode for the 2027 model year that simulates eight gears without adding a single one.
Does an electric car motor need servicing?
Very little. No engine oil, no timing belt, no clutch, no spark plugs. What remains is the drivetrain coolant and, depending on the brand, the reduction-gear oil, to be checked in your model's service book. Our maintenance guide lists the intervals by manufacturer.
Why does a powerful electric car pay more tax in Wallonia than in Flanders?
Because Wallonia calculates its registration tax with a coefficient that rises with kilowatts: 0.01 up to 120 kW, then 0.10, 0.18 and 0.26 above 250 kW. Since 1 January 2026, Flanders applies a flat €61.50 at registration and €107.16 a year, whatever the power.
What is a rare-earth-free electric motor?
A motor that does without neodymium magnets, whose mining and refining are concentrated in China. An induction motor has no magnets at all; a wound-rotor synchronous motor creates its field with current sent into the rotor. The Renault 5 E-Tech and the new-generation BMW iX3 use one on the rear axle.
Le verdict de Christophe F.
Do not choose an electric car for its motor type: magnets, wound rotor or induction, all three do the job, and consumption depends far more on weight and aerodynamics. Look at its power in kW instead if you live in Wallonia, where the 120 kW and then the 155 kW thresholds make the registration tax jump. In Flanders and Brussels, the amount is the same for all. The comparison tool shows the power of every version sold here, enough to decide before you sign.
