motor · powered wheelchair · 技術 101 · 電動輪椅 ·Dec 17, 2024

Electric wheelchair - brushed motor vs brushless motor

Electric Wheelchairs - Brushed Motor vs. Brushless Motor

Electric Wheelchairs - Main Factors Affecting Price and Power:

Motor Horsepower and Type (Brushed Motor vs. Brushless Motor)

	Brushless Motor (Light, Durable, Power-efficient)	Brushed Motor / Permanent Magnet Motor (Cheaper)	Brushed Motor with Worm Gearbox (Fast Start, High Horsepower)
Appearance	Compact size Flat, disk-shaped	Larger size Flat, disk-shaped	Large size Long, cylindrical
Control Box Wiring	Required Thin wires	Not required Thick wires	Not required Thick wires
Self-locking function when powered on (Electronic Brake)	Yes	Yes	No
Electric Wheelchairs - Detailed Technical Comparison of Brushed vs. Brushless Motors
Weight	~2-4kg	~2.5-5kg	~3-7kg
Efficiency	Approx. 80-90%	Approx. 65-80%	Approx. 65-80%
Battery Life Comparison	Approx. 1 hour with a 3Ah battery	Approx. 1 hour with a 3.5Ah battery	Approx. 1 hour with a 5Ah battery
Advantages	Light, durable, power-efficient	Inexpensive, low torque	Fast start, high torque with worm gear, easy to maintain
Disadvantages	Relatively expensive, difficult to manufacture	Power-consuming, difficult to maintain, noisy and hot, shorter lifespan	Heavy, power-consuming, requires maintenance, weakens over time
Used for	New lightweight electric wheelchairs	Affordable electric wheelchairs	Traditional electric wheelchairs
Common Motor Power	150W-250W	150W-250W	200-450W
Controller Connection	Requires amplification of signal through a computer box (drive)	Directly connected to the battery and left/right motors	Directly connected to the battery and left/right motors
Operating Experience	High-quality ones: Very smooth. Budget ones: Computer control box may "jump," choppy performance.	Smooth start, but may feel out of control on slopes or when high power is needed.	Smooth start Continuous control, current reaches the motor instantly, fast and stable response.
Recommended Products	250W Quickie Q50R Carbon and Carbon XC+	None	High-performance electric wheelchair series - such as GX320 & DMC-III series

Motor Appearance and Control Box

Brushed Motor
- Larger in size, heavier, mostly long cylindrical design.
- Or permanent magnet motors, which are flat and round.
- Typically no external control box.
Brushless Motor
- Smaller in size, lighter, compact casing, mostly flat, disk-shaped design.
- Usually equipped with a control box at the bottom.

Brushed Motor Structure

This is a more common type of motor. Its advantages are its low price, fast starting and braking, and potentially high horsepower, but its disadvantages are heavy weight and low efficiency. Due to mature technology, it is easier to achieve high-power motors. However, brushed motors are not suitable for operation at high temperatures, as high temperatures can soften the springs in the carbon brushes (due to "tempering"), causing their efficiency to decrease over time.

Example of carbon brushes in an electric wheelchair brushed motor:

Most of the time, when an electric wheelchair motor feels weak after prolonged use, simply replacing the carbon brushes may resolve the issue.

Brushless Motor Structure

This motor type does not use carbon brushes/rotors for commutation. Its advantages are that there are no carbon brushes acting as current commutators (no rotor), so there is no wear and tear from carbon brush friction to clean, maintenance is simpler, and efficiency and lifespan are higher and longer. Since it does not require large magnets and coils, losses are reduced, and it is also lighter and smaller in size. Due to the higher manufacturing difficulty and cost, it is more expensive, and currently, there are not many high-power brushless motors available on the market.

Performance Considerations

Smoothness and Response Speed

Brushed motors offer immediate power output due to direct signal transmission, suitable for situations requiring quick response.
Brushless motors may exhibit discontinuity due to signal delay, but this can be improved with high-quality controllers.

Torque and Power Output

Brushed motors (with worm gear) are suitable for high torque demands, such as climbing slopes or carrying heavy loads, where their high current handling capability is ideal.
Brushless motor power is typically lower, but their performance is gradually improving with technological advancements.

Summary

Brushed Motor

Advantages: Inexpensive, powerful (when paired with a worm gearbox), fast response
Disadvantages: Heavy, power-consuming, requires maintenance, weakens over time
Commonly used in: Traditional electric wheelchairs

Brushless Motor

Advantages: Lightweight, durable, power-efficient
Disadvantages: Expensive, rare in very high power versions, requires entire assembly replacement if broken, needs a compatible controller
Commonly used in: New lightweight electric wheelchairs

Summary and Recommendations for Brushed and Brushless Motor Use:

Lightweight and Power-efficient -＞Brushless motor electric wheelchairs

Affordable for flat surfaces -> Brushed motor (Permanent Magnet Motor)

High power and simple maintenance -＞Brushed motor with worm gearbox electric wheelchairs

DC brushed motors typically offer a smoother operating experience due to their simpler control mechanism; however, with advancements in brushless motor technology, the performance gap in handling is narrowing. The choice of motor should be based on specific needs, such as power requirements, maintenance preferences, and budget considerations.

By the way: In Cantonese, "Motor" is called "摩打" or "馬達", while in mainland China it's called "電機" (diànjī).
Brushless motors are called Brushless Motor, and brushed motors are called Brushed Motor.
Electric wheelchairs usually use direct current, i.e., DC, so brushless motors are often called BLDC.
If you see products using "電機", it's usually from mainland China.

Related Articles:

How to Choose an Electric Wheelchair - Brushed Motor vs. Brushless Motor Controllers

Lightweight Electric Wheelchair Buying Guide