What an electric motor does
Turning electrical energy into rotating mechanical work, and why EVs are built around this trick.
You'll learn
- Explain what an electric motor does at engineering level
- Read the numbers that define the behaviour
- Apply the idea to a real drive unit
Overview
An electric motor converts electrical energy into mechanical rotation using nothing but magnetic fields — no combustion, no linear-to-rotary conversion, and far fewer moving parts than an engine.
In depth
Motor explorer
Explore an EV drive motor
Rotate through the main views and tap any hotspot to learn what it does.
External · 10 components
Why EVs use electric motors
A combustion engine burns fuel to make heat, turns that heat into pressure, and pressure into reciprocating motion that must then be converted to rotation through a crankshaft. An electric motor skips straight to rotation, which is why it can be over 90% efficient against roughly 30-40% for a good petrol engine.
| Property | Combustion engine | Electric motor |
|---|---|---|
| Moving parts | Hundreds | Roughly one (the rotor) |
| Peak efficiency | 30-40% | 90-97% |
| Torque at 0 rpm | Near zero | Near maximum |
| Useful rev range | 2,000-6,000 rpm | 0-20,000 rpm |
Key takeaways
Remember this
- An electric motor converts electrical energy directly into rotation via magnetic fields.
- Electric motors are dramatically simpler mechanically than combustion engines.
- Torque is available from zero rpm because it depends on current, not airflow.
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