Small Brushless but Quietly Efficient Motors

Brushless motors have numerous advantages, penetrating use not only in DC applications but also increasingly in AC ones. As there are no brushes requiring periodic maintenance to avoid sparking from wear, they are quiet, light and safe. BLDC motors also have no other mechanical parts such as commutators or slip rings. Their rotors require no windings, unlike those used in brushed motors. This straightforward design ensures minimal electromagnetic interference as well.

In terms of performance, BLDC motors surpass their traditional brushed counterparts. They generate less heat and have an efficiency of 85 to 90 percent compared to the latter's 75 to 80 percent range. That these units can be run by an MCU is another plus factor, allowing precise and programmable control. They also have a longer operating life span.

Due to these benefits, the category has breached applications normally associated with AC motors. As well as their de-facto use in electronics that run on DC supply, BLDC units can now be found in washing machines, air conditioners, coffee machines, mixers, bread cutters and hairdryers.

In battery-operated devices such as robotic vacuum cleaners, power tools and RC toys, they are popular with product designers because their efficiency helps prolong battery life.

For the same reason, brushless motors are used in electric vehicles, which require lightweight and energy-efficient onboard solutions. In the wider automotive industry, they are increasingly adopted to drive add-on enhancements such as motorized seats, mirrors and sunroof systems.

In personal, professional and industrial service robots, BLDC units are also winning over electric counterparts.

China's brushless motors

One of the largest production bases for brushless motors, China has been reaping high growth gains in recent years. Despite the pandemic, its market reached $5.76 billion in 2020, rising from $4.8 billion the previous year, according to the Qianzhan Research Institute. In 2021, the estimated value is $6.92 billion, and is expected to grow by about 20 percent the following year to total $8.3 billion.

Taken against global figures, the country accounted for nearly 30 percent of the brushless motor market in 2019 and will have nearly 38 percent in 2021. According to Grand View Research, brushless motors posted $16.3 billion in 2019 and are forecast to achieve $18.5 billion in 2021. The business consulting firm says the worldwide total will increase further to $27.2 billion by 2027.

For their part, many Chinese manufacturers are pushing efficiency levels of their brushless motors to 90 percent and higher, aiming to sharpen their competitive edge in this lucrative market. Most are currently offering products with a rating above 80 percent.

Further miniaturization remains on the product development agenda as well, as this is emphasized in many applications. Leader Micro Electronics (Huizhou) Co. Ltd has released brushless DC motors measuring 8mm in diameter and 2.5mm in thickness. In comparison, widely available diameters in the domestic market start at 20mm.

A few others explore new technology for greater differentiation. A subsidiary of SUMEC Group, for instance, built the National-Local Joint Engineering Center on Rare-earth Permanent Magnet Brushless Motors. This facility, tasked with developing high-performance products for the industrial and robotics markets, has already yielded several patents. It will continue to pursue breakthroughs in this product category as well as in materials.

Manufacturing pool

More than 80 percent of the hundreds of suppliers of brushless motors in China are homegrown companies, mostly operating on a small or medium scale. Moons, Broad-ocean, Hetai and Weizhen are some of the larger ones.

Brushless motors make up between 30 and 90 percent of shipments of both foreign and domestic manufacturers in China. All such suppliers also offer other types of motors, including brushed kinds.

The category's fast growth thanks to increasing demand in the mobile electronics, home appliances, automotive, medical and industrial sectors is driving production expansion. According to manufacturers interviewed by Global Sources Electronic Components, many are planning to raise output by 10 to as much as 20 percent, expecting overseas shipments alone will be up by 10 percent in 2022.

The majority of Chinese suppliers export their products, mainly to Europe, the US and the Asia-Pacific region.

Brushless motors come mostly from the provinces of Guangdong, Zhejiang and Jiangsu, China's established manufacturing powerhouses.

Typical brushless motors

China manufacturers offer brushless DC and AC synchronous motors for smart home, automotive, robotics, industrial and security applications. BLDC units dominate output.

Based on rated voltage, there are 6, 9, 12, 24, 36, 48, 60, 72, 110, 220 and 380V versions. In terms of rated power, the options range from 30 to 750W in BLDC units and up to 5kW in AC synchronous types.

As for sizes, motors 20, 24, 28, 36, 42, 57, 86, 110 and 130mm in diameter are widely available.

These are also water-resistant designs, mostly with an IP55, IP65 or IP67 rating.

Key materials used in the production of brushless motors include stators, rotors, magnets and shells. These come from domestic or foreign providers, depending on customers' requests.

The cost of these inputs rose slightly in the past 12 months, resulting in 5 to 10 percent higher product prices. It remains to be seen whether costs will stabilize before the end of the year or in 2022.

≥150W four-pole brushless DC motor

This four-pole brushless DC motor from Guangzhou Ruibao Electrical Co. Ltd, the 57BLDCS, has 3,000rpm speed and 0.5N.m torque. This ≥150W unit, with a class B insulation, has 48V input voltage, 5.7A rated current, 0.8ohm±10 percent resistance, 100Mohm minimum insulation resistance at 500VDC and 600VAC dielectric strength at 50Hz, 1mA, 1sec.The negotiable minimum order has a seven-day lead time.

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13,000±3,000rpm brushless DC motor

Rated at 3VDC, 80mA, this LD 0825 BLDC motor from Leader Micro Electronics (Huizhou) Co. Ltd has 13,000±3,000rpm speed, more than 10Mohn insulation resistance and -30 to70 C operating temperature. The startup voltage is 2.5VDC. Dimensions are 8x2.5mm.The minimum order is 100 units. Delivery is within seven days.

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24V-rated brushless DC motor for barbecue grills

Suitable for use in barbecue grills, this BLDC-3816 brushless DC motor from Shenzhen Yunhongda Motor Co. Ltd has 45,000rpm±10 percent no-load speed. Its rated voltage and maximum no-load current are 24V and 3A.The minimum order of 1,000 units is delivered within 10 days.

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Brushless DC motor with 104mN.m rated torque

Sinopro Electric Motion (Shenzhen) Co. Ltd's SEM5520024HR & SEM5520024R brushless DC motor has 3,700rpm±10 percent no-load speed, 104mN.m rated torque and more than 3,000-hour endurance performance. Its rated voltage is 24VDC, no-load current 0.5A, operating current 2A and rated power 35W.The supplier requires a minimum order of 1,000 units. Lead time is 15 days.

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