China Sourcing of World Class Motor Components: BLDC Motors & More

Sinotech    August 26, 2013

Automatic Machining of Motor ShaftsManufacturers who build DC gear motors, BLDC motors and other components often look to China to source components like brushes, magnets, and wound coils to keep costs low and maintain a competitive edge. While China offers attractive benefits in regards to sourcing, it’s not without risks when it comes to the engineering of a component.

Outsourcing Approaches

There are several ways companies can source their BLDC motor and DC gear motor components:

  • Direct approach: When a company wishes to work directly with a Chinese factory, it must find the right factory, negotiate a price, and supervise the production for quality assurance.
  • Using a third party:  A third party, like Sinotech, has offices in the U.S. and China. Sinotech’s bilingual staff works onsite in the Pacific Rim to negotiate with factory sales managers and supervise production on a client’s behalf – all while operating on U.S. time and under U.S. law.

On-site Audit - Testing of Motor ComponentsIssues Related to Sourcing World-Class Motor Components


While commutators from China are generally of good quality, it’s wise to inspect the factory’s copper and resin raw materials. Make sure the factory has material certifications for the copper, acquires its phenolic materials from well-known suppliers, and has a metallurgy lab to test the hardness and purity of its materials. During inspection also verify that the factory controls its progressive die stamping process. The best factories do a 100% visual inspection of the commutators and perform 100% breakdown testing using a hipot tester.

Graphite Motor Brushes

Graphite motor brushes are generally simple to make. During an inspection, an auditor should check the storerooms to inspect raw materials like lead wire, graphite powder, and copper powder for organization and material certifications. The ovens should be well calibrated with certificates traceable to a national standard.

Motor Shafts

Motor shafts are one of the most challenging components to source because of their complex geometry, hardening requirements, and the difficulties in finding shaft alloys. When a Chinese company produces precise hand-ground samples, this doesn’t mean the finished products will have the same results. The best factories are those with highly automated processes and sufficient fixturing.

Lamination Stacks

China has lamination stacks readily available. Keep in mind that it may be difficult to find small volumes of lam stacks in English-dimensioned thicknesses since many are metric-dimensioned. Also, many Chinese factories are not highly motivated to sell lam stacks since many of these factories also produce motors that represent higher profit margins.

Motor Magnets

China is one of the best and most economical resources for the production of ceramic motor magnets. When a company wants to source its magnets, it should send the specifications of the magnet it wants along with its measurements, maximum number of chips, and the required surface porosity.

Neodymium Magnets

When sourcing neodymium rare earth magnets, verify the quality of the magnet’s plating along with the plating’s uniformity and thickness. There should be an absence of pinholes in the plating, particularly at the corners. In sampling neodymium magnets from China be sure to pay close attention to plating uniformity and thickness.

Wound Coils

Most motor assembly factories in China have winding workshops for the armatures and stators, so the key is finding a factory that’s willing to sell its winding services. Be cautious when choosing the wire and insulating materials, and have an independent laboratory test a wire’s thermal properties and look for pinholes in the insulation.

BLDC Motors

Sinotech’s aim is to provide clients with solutions that are tailor made for their requirements without compromising on time, cost and quality. Sinotech specializes in the manufacturing of brushless DC motors. Our manufacturing process is monitored by a team of experienced auditors and professionals. We ensure that our processes meet the set quality standards. All the processes of manufacturing are reviewed on a regular basis for criticality and priority.

Sourcing DC gear motor and BLDC motor components to China can be a great way to cut costs. Let Sinotech help you with this process. Our experienced bilingual and bicultural team hand-picks the best factories and personally supervises the production of your product on site. As a U.S.-based company, we operate under U.S. laws and offer product liability insurance. Contact Sinotech to find out how our services stack up against other offshoring options, or request a quote for your project.


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