Changzhou Yunkong’s CE-approved model YK57BL brushless motor has a 57mm frame and 46 to 112mm body length. It may include a built-in driver.

Suppliers increase the line’s share of their DC motor output, and direct R&D toward more-efficient and advanced types.

China makers of brushless motors sustain initiatives to grow the category in response to the trend shift from traditional brushed kinds. They are taking advantage of climbing requirement in the home appliances, office automation, automotive, medical, instrumentation, industrial, military and aerospace fields. Companies look forward to the projected sales increase surpassing 15 percent by end-2014.

At Shenzhen Power Motor Industrial Co. Ltd, brushless units will account for 7 percent from 5 percent of its total DC motor yield by year-end. Changzhou Yunkong Electronic Co. Ltd churns out the former type only.

To complement expansion efforts, suppliers are pursuing product upgrades to keep up with overall developments in the line. They are preparing for the anticipated rise of sensorless and integrated units. The former helps improve system reliability, in addition to lowering manufacturing costs. This is because the number of electrical connections is reduced, problems with mechanical alignment are eliminated, and smaller and lighter configurations can be achieved. The use of indirect sensing of the back electromotive force, however, poses a technical difficulty at present. As a result, the technology is not widely adopted yet but its advantages are expected to prevail in coming years. For this reason, Shenzhen Power has allocated about 80 percent of output for sensorless units.

Integrated varieties combine the motor and electronic driver in one packaging, eliminating the mismatch among components and wiring errors, enabling more-compact forms, and reducing total outlay. Shenzhen Power is among the few local companies that can produce this type, and it does so only to accommodate buyers’ requests. Globally, the subcategory is steadily gaining steam. Shipments are predicted to post nearly 12 percent CAGR between 2009 and 2015, according to IMS.

In addition to advanced types, China companies are releasing coreless variants, which boast high power density, torque and efficiency, and a wide speed range. Without the iron core, the kind has low starting torque, and no torque fluctuation and cogging for smooth running. Enhanced volume power ratio, low temperature rise and lightweight configuration are its other advantages. Shanghai Mindong Mechanism Electron Co. Ltd has the BMP62, a series of 62mm coreless models.

The worldwide segment is expected to maintain about 10 percent annual sales increase in coming years. This is encouraging domestic suppliers to raise theirgrowth targets in the months ahead.

Shenzhen Power anticipates a 60 percent revenue increase by end-2014. It added one production line in February and plans to install another in June. Once both are operational, monthly production capacity will reach 30,000 units or a 60 percent boost. The company has taken on the manufacture of drivers as well. Previously, the components were outsourced.

Changzhou Yunkong plans to raise sales by 30 percent this year. The maker said its current capability can handle the projected increase in requirement.

Shanghai Mindong targets about 20 percent higher revenue and Shenzhen Xinhe Motor Co. Ltd, 15 percent. Both suppliers generate 50 percent of revenue from brushless motors.

Mainland China has more than 200 makers of brushless motors, churning out one-third of global output. The majority of these companies are locally owned. The rest of the pool includes international players such as Nidec, Mabuchi, and Taiwan- and Hong Kong-invested businesses.

Most suppliers are based in the Pearl River and Yangtze River Delta regions, specifically in Guangdong, Jiangsu and Zhejiang provinces.

Mainstream selection

Brushless motors from mainland makers have input voltage of 5, 12, 24, 36 or 48V, and rated power ranging from 1W to 7.5kW. These support less than 100 to 40,000rpm rated speed, 60 or 120-degree phase angle and 80 to 90 percent efficiency. Based on the bearing, the typical life span surpasses 20,000 hours. Most units have undervoltage, overcurrent and short-circuit protection.

By rotor position measuring method, there are sensored and sensorless types. Hall sensing devices are widely used in the former kind for their low cost.

Products are classified further by structure, covering those with outer and inner rotors. Releases based on the latter are structurally simple and are the common type offered.

Versions with an optical or magnetic encoder are also available. These target applications requiring high precision dynamic positioning.

In terms of magnetic materials adopted, there are rare-earth, alnico and ferrite models. Motors employing NdFeB dominate supply. Interviewed suppliers Shanghai Mindong, Shenzhen Xinhe and Changzhou Yunkong utilize NdFeB inputs, while the ratio at Shenzhen Power Motor is 90 percent.

Manufacturers generally accommodate customization based on buyers’ voltage, current, power, speed, torque and dimensions requirements.

The main components and materials used in brushless motor production include stators, rotors, bearings, drivers, enameled copper wire, magnetic inputs, electric wire and metal.

Makers source chips for the drivers mainly from foreign providers such as TI, Freescale, Fairchild and Atmel. Some obtain bearings from Japan companies.

Although material costs are stable, labor expenditure and the yuan value continue to climb. Suppliers, however, plan to maintain prices until year-end to attract more orders.

Product gallery

Changzhou Yunkong Electronic Co. Ltd
(China)
Model: YK57BL
MOQ: 500 units
Delivery: 30 days
Description: Custom parameters; 57mm frame; 46 to 112mm body length; built-in driver optional; CE

Shanghai Mindong Mechanism Electron Co. Ltd
(China)
Model: BMP62
MOQ: 50 units
Delivery: 30 days
Description: Coreless, 62mm; 3,000, 4,700 or 6,500rpm rated, 4,020, 6,030 or 8,040rpm no-load speed; 0.52N•m rated torque; 12 to 48VDC operating voltage; 163, 256 or 354W power output; 80, 82, 84 or 86% maximum efficiency; 110 C maximum permissible rotor temperature; 73mm length; 0.83kg

Shenzhen Power Motor Industrial Co. Ltd
(China)
Model: PBL-3935230
MOQ: 1,000 units
Delivery: 30 days
Description: 13,001rpm no-load speed; 122.4mN•m torque; 0.275 no-load current, 33.02W input; 230V, 50Hz; 124W output; for handheld blenders

Shenzhen Xinhe Motor Co. Ltd
(China)
Model: XH-BL5860-01
MOQ: 500 units
Delivery: 35 days
Description: 2,000 to 10,000rpm, clockwise or counterclockwise rotation; 0.1 to 1N•m torque; 10, 12, 18, 24, 36, 48 or 310VDC, 110 or 220 to 240VAC, 50/60Hz; <60dB noise; NdFeB magnet; speed-adjustable; 5,000hr life span; 58mm motor diameter, 60mm length, custom shaft size; 0.8kg