DC motors for electric vehicles, "green" products gain momentum

	The model D525-01326 brushless DC motor from I.CH Motion features 3,500rpm speed and is suitable for massage chairs.

China suppliers of DC motors are combining product upgrades and capacity expansions to boost quality and yield toward meeting robust overseas demand. Applications are widening, with automotive and energy-saving electronics seen as key growth areas. Motors for electric vehicles and “green” devices, in particular, are gaining maker support. Rising orders for the latter have in fact helped secure the market lead of brushless motors. This type is expected to remain the best-seller in coming months.

Rare-earth permanent coreless motors, meanwhile, are gathering momentum in the high-end category. This variant is highly reliable and does not warm up significantly when running. The small, lightweight kind abandons silicon steel altogether and reduces the use of copper and ordinary steel by 50 percent and 80 percent, respectively. The main applications are wind power systems, water pumps, compressors and portable power plants.

In step with the upmarket shift, R&D efforts are geared toward extending the life span, lowering noise and enhancing torque. Manufacturers are also seeking to reduce the size and weight while enhancing precision. Some, including I.CH Motion Co. Ltd, have developed motor drivers that match seamlessly with motors. The integrated design can decrease the failure rate of servo systems and are suitable for miniature electronics.

Meanwhile, production capacity expansion initiatives are under way in preparation for surging orders. I.CH Motion, for instance, has opened a new factory that is thrice as large as its existing facility.

Exporters are quick to take advantage of recovering economies. Most have increased their shipment volumes. Emerging markets such as Brazil, Russia, Southeast Asia and India are being explored as well.

Manufacturers are also undertaking several strategies to counter rising raw material and labor costs. Some have begun making their own components, while others are ramping up capacity to achieve economies of scale. Shenzhen Kinmore Motor Co. Ltd, for example, has increased new hires by 40 percent. Guangzhou Huiyun Science and Technology Co. Ltd purchased automatic production equipment to reduce manual work.

China has more than 1,000 suppliers of DC motors. Many are based in the Pearl River and Yangtze River Delta regions. The former has a longer history of making motors, while the second has been posting a higher growth rate in recent years.

The other sourcing hubs are Changzhou and Fu’an in Jiangsu and Fujian provinces, respectively. The latter area is the production center for small and medium DC motors, accounting for one-third of the country’s total output for these types. In 2010, the city’s motor exports recorded 70 percent growth.

Shandong and Zhejiang provinces also host a number of manufacturers.

Brushed DC motors dominate
Manufacturing inputs
Hong Kong: Micro, step DC motors targeted
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DC motors from China suppliers may be classified into brushed and brushless depending on the structure. The first continues to account for more than half of the total output, thanks to its lower costs yet high reliability and simple speed controls. The product, however, requires maintenance and has a short life span for high-intensity use, which opens up the market for brushless variants.

Based on magnetic field type, the lineup covers permanent and nonpermanent motors. For magnetic field generation, there are versions with permanent magnetism and those featuring electrical current-induced. Self-strengthening models are further subdivided into field coils in series, parallel, shunt and compound.

In terms of terminal applications, DC motors may be either drivers or controllers. As regards speed, buyers will find high-, low-, constant- and gear change-speed releases.

DC gear motors are available in planet, worm or helical configuration. Small and midsized versions of the first are the most common.

Export-bound products conform to UL, CSA, VDE, TÜV, CE, CCC and RoHS. Quality systems meet ISO 14001 and 9001:2000, and ISO/TS 16949 requirements.

Guangzhou Huiyun concentrates on brushless DC motors, which it classifies according to diameter. The company’s output is dominated by 49, 59, 63, 76 and 88mm models.

Shenzhen Kinmore has launched a high-voltage yet lightweight, quiet and efficient DC motor for blenders, juicers and grinders. It also offers a series of automotive and gear versions. The export-oriented maker doubled its shipments last year.

Shenzhen Topband Co. Ltd utilizes its expertise in intelligent control boards to develop a variety of brushless and coreless units. The main applications are home appliances, electric vehicles and model airplanes, medical equipment, scientific instruments and power tools. Its high-end releases have an 85 percent efficiency and low noise in a small form factor. Most of the company’s yield ships to Europe, but plans are afoot to expand to the US. Like Shenzhen Kinmore, Shenzhen Topband posted more than 100 percent annual growth in overseas shipments last year.

Over half of I.CH Motion’s products are brushless DC motors for industrial tools, office equipment and home appliances. The enterprise also exports drivers that match the motors seamlessly, an integrated design that reduces the failure rate of servo systems effectively. Its DC gear motors are applied in industrial control. The 6V pear-shaped D482G1 model has a speed ratio that suits safe boxes and instruments. The torque is between 2 and 6kg•cm, and the dimensions are 32x20mm. The company also has a 52x100mm top-grade brushless motor with a rated power, speed and torque of 50W, 3,500rpm and 13N•cm.

The key components for production are the stationary and rotating electrical magnets, copper wires, silicon steel sheets, axes, commutator pieces, carbon brushes and plastic brush holders. Brushless motors also have magnetic sensitive Hall position sensors and photoelectric transducers to replace the carbon brushes. These sensors add to a unit’s heft and bulk, and increase maintenance work, giving rise to a new generation of brushless DC motors without the component. Other elements include rotating parts, shafts, ball bearings and wires.

More companies are adopting permanent magnets to take advantage of their high torque/power densities, efficiency and reliability. They are also tapping the abundant domestic supply.

Options for permanent magnets include ferrite, AlNico, SmCo and NdFeB alloys. The first is the least expensive but has weaker magnetic properties than the other three. NdFeB, the newest to be commercially available, is the best choice for the stationary part of DC motors. It costs more than ferrite, but less than SmCo.

Brushless motors employing NdFeB have the advantages of enhanced efficiency and torque at low noise, making them cost-effective and thereby suitable for the high-end bracket.

Companies purchase more than 80 percent of raw materials domestically, and the rest from Japan. The typical partners are Zhong Ke San Huan for NdFeB magnets, and Wisco and Shanghai Baosteel for silicon steel. The source and type of components can be customized on request.

DC motor prices depend on the product type and energy efficiency. Brushless variants go for $17 to $50. Brushed and gear models are below $15.

With spending on permanent magnets climbing in recent months, some suppliers raised quotes by 10 percent.

As part of cost-reduction measures, manufacturers are optimizing processes. Some are investing in advanced equipment.

DC motor suppliers in Hong Kong are setting their sights on more complex, higher-value models under efforts to boost margins. Brushed motors currently lead the output of most manufacturers. Although brushless designs are available, demand remains slow so the yield will not likely rise substantially in coming months.

Makers are developing micro and step variants for high-tech devices. Complementary initiatives aim to enhance suppliers’ technical capability to provide complete solutions. Enterprises are also looking to shorten response time to inquiries and waiting period for quotations and samples.

Many now set aside a portion of sales for investment in newer and advanced production and testing equipment. Operations positioning themselves as one-stop solution providers also offer electronic module assembly services.

In the face of the appreciating yuan and rising labor and material expenditure, more Hong Kong suppliers are adopting global management standards to increase efficiency, manage costs and sustain competitiveness. Most maintain large R&D teams and cooperate with university research institutions to preserve their technology edge.

The bulk of the 20 plus enterprises in the territory export a sizable portion of output to mainland China. With the global economy recovering, however, more companies are considering other export markets, in particular North America and Western Europe.

Once Top Mfy Ltd offers brushed and brushless, gear, coreless, curtain and step motors used in power tools, automotive products and household appliances. The maker said it has a 90 percent repeat order rate. Johnson & Johnson, LG and Midea are among its OEM and ODM clients.

Suntech Development Co. Ltd’s selection includes customized DC types for toys and electrical products, and vibration, brushless, gear and mini gear versions for automated control systems.

Teco Electric Co. Ltd supplies both DC and AC motors, offering core/coreless, brushed/brushless, micro, gear and mini dynamo variants.

Guangzhou Huiyun Science and Technology Co. Ltd
(mainland China)

Model: D76 Series
MOQ: 500 units
Price: $17
Description: Wire feed type; 12 to 48V voltage; 45 to 120W power; 60:1, 30:1, 20:1 gear ratio; 25 to 80rpm, 150 to 220rpm speed; right or left gear box

Once Top Mfy Ltd
(Hong Kong)

Model: OT-SM065L-001
MOQ: 5,000 units
Description: Stepping type; 3V voltage; 33ohm resistance; 2,000pps starting frequency; 5,000pps slew speed; 18-degree step angle; 2-phase bipolar drive; for digital video cameras, Blu-ray players

Pro Motor Electric Co. Ltd
(Taiwan)

Model: APR365GB-07
Description: Gear type; 24VDC constant voltage; 0.05A maximum current; 35g•cm torque; 4,550rpm±12% speed; for vending machines

Shenzhen Kinmore Motor Co. Ltd
(mainland China)

Model: RS-7912SHFC2J2
MOQ: 2,000 units
Price: $5
Description: HVDC type; 2-pole stator, 12-slot armature, 24-slot commutator; zinc-coated steel strip housing and end cap; 5mm stainless steel shaft; Class F magnet wire; 42.2x75.5mm; for food blenders, juicers, grinders; CE, VDE, UL, RoHS

Shenzhen Topband Co. Ltd
(mainland China)

Model: CL3570
MOQ: 500 units
Price: $30.70
Description: Coreless type; 12 to 48VDC voltage; 10 to 90W power output; 0.1 to 0.6N•m rated, 0.4 to 1.2N•m stall torque; 2,000 to 8,000rpm no-load speed; 80% efficiency

Suntech Development Co. Ltd
(mainland China)

Model: SF1215-13115
Description: 2.4V nominal, 1 to 3.5V operating voltage; 0.29W power output; 2.3g•cm torque; 15,000rpm no-load, 12,310rpm maximum speed; 48.8% efficiency

Teco Electric Co. Ltd
(Hong Kong)

Model: RF330-11400
MOQ: 5,000 units
Description: RF micro type; 2.5V nominal, 1 to 6V operating voltage; 2,800rpm no-load speed