QS180 Mid Drive Motor – Core Advantages of Inner Rotor Design
Structural differences between outer rotor hub motors and inner rotor PMSM motors lead to massive gaps in top speed, heat dissipation and continuous power performance, which directly impact riding experience and motor service life.
How Outer Rotor Hub Motors Work
For traditional outer rotor hub motors, the rotor is arranged on the outer ring while the stator sits in the center. This design delivers instant low-speed torque for easy climbing, yet it comes with obvious drawbacks:
· Limited maximum no-load RPM, unable to support high-speed cruising;
· Poor heat dissipation structure. Heat generated during operation is trapped inside the closed wheel hub, with no efficient way to release heat outward;
· Prone to thermal attenuation under long-time heavy loads. Sustained high-temperature operation will demagnetize the internal magnets and shorten the motor’s lifespan drastically.
Core Superiority of PMSM Inner Rotor Motor QS180
Our 8000W PMSM inner rotor motor adopts an opposite layout: the rotor is placed inside the motor housing, and the stator wraps around the inner rotor. This open-body structure solves all heat and speed pain points of hub motors:
· Excellent heat dissipation performance
Heat produced by the stator windings transfers directly to the large ribbed outer housing during high-speed operation, achieving efficient air cooling. There is no heat accumulation inside the motor core even under long heavy loads.
· Ultra-wide high-speed range
The motor reaches a no-load speed of 4300–6000 RPM, far exceeding the speed limit of conventional hub motors, perfectly matching high-speed electric motorcycles and performance conversion kits.
· Stable continuous high power output
Benefiting from reliable heat dissipation, the motor supports a steady continuous power of 18kW alongside a 20kW peak power output. It maintains stable power delivery during long-distance high-speed rides, steep hill climbing and heavy cargo transport without power drop caused by overheating.
Extra Premium Design Highlights
– Built with 90mm high magnets and 4 pole pairs to balance strong torque and high rotation speed;
– IP67 waterproof grade + waterproof encoder sensor, adapting to all-weather riding scenarios;
– Max efficiency up to 94% to cut power consumption and extend battery range;
– Equipped with PT1000 temperature sensor to monitor internal temperature in real time, adding extra overheat protection.
This inner rotor motor QS180 is the ideal upgrade choice for high-performance electric motorcycles, high-speed e-bikes, heavy-load electric two-wheelers and aftermarket EV conversion projects, for users chasing both top speed and durable reliable power.
