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Current Activities(HKTDC Electronic Components & Parts, Vol 01,2009)



Mainstar Industries Ltd is a specialist in custom-made electromagnetic components including transformers and chokes
While digital and wireless technology advances on all fronts, traditional transformers and coils continue as indispensable items in the electronics industry. This is good news for Mainstar Industries Ltd, a specialist in custom-made electromagnetic components.

"Our plant on the Chinese mainland is technically very well equipped and advanced for the production and on-time delivery of quality electromagnetic components such as switching power transformers, miniaturised transformers, line filters, pulse transformers and coupling transformers, toroidal chokes and inductors," says Sales Coordinator Sharon Chan.

"Most of our products are tailor-made according to customer's requirements, and are top value as we know how to provide precise technical specifications at the right price," she adds. Customers include such household names as Panasonic and Hong Kong's MTR Corporation.

Solid foundations

Mainstar was founded after the proprietor had established relations with a Taiwanese electronics manufacturer who sought a producer of modem transformers to fill an urgent order.

"What was required was not readily available on the market as the specification called for a quite special, high-class transformer," Ms Chan relates. "Mainstar was formed in Taiwan to meet the need."

Initial production quantity was just 300,000 transformers a month. "Then, in 1993, we won a contract to manufacture chokes for a major Japanese group," she adds. "The specification proved very demanding and the quality requirement was so high that the client installed its own engineers to oversee the work and train our staff," she adds.

With that experience under its belt, Mainstar found it could cope with demand for a variety of electromagnetic products. "For example, we started to produce electro-luminescence transformers that are used for the back-lighting function in clocks," says Ms Chan.

"Today, we are quite broad in our offerings, with many types of transformers for electronic devices, computers and audio equipment," she adds. "Models vary according to destination, as there are different safety standards for the US, the UK and Germany. We always send samples for testing to an independent, approved laboratory to ensure compliance with various international standards such as UL, CSA, VDE and CE."

With a focus mainly on transformers rated below 100VW, Mainstar has a popular range of audio transformers, with split bobbin and other lead configurations available; low-cost filters; common coils and power inductors suitable for use as line filters in switching power supplies; and line filters for AC adaptors used with battery chargers.

"We also supply small-size, low-profile transformers for voice and data modem applications in standard and custom designs," Ms Chan says. "There are also high-frequency (HF) transformers tested at 1750V RMS or 3750V RMS Hipot standard."

Plentiful products

Other communications items include EL transformers, EMI line filters, ISDN transformers, pin cushion transformers, switching power transformers, toroidal chokes and voice transformers.

"The common mode EMI line filter is designed to prevent noise emissions in switching power supplies," Ms Chan says. "They are also used to prevent high-frequency noise in communications equipment such as facsimile machines."

Typical electrical specifications include a rated voltage of 250V AC at 50-60 Hz; a dielectric strength of 3kV AC; and a coil-to-coil insulation resistance of 100 Megohms (minimum at 500V DC).

Basic raw materials include copper, ferrite, nickel-steel and, if required, printed circuit boards. "All materials and components used are RoHS-compliant, so we need to pay attention to the quality of incoming materials," assures Ms Chan.

Interestingly, Mainstar also has a policy of not allowing any one client to command more than 15% of total sales. "We want to remain flexible and to spread our business over several popular lines as it would be too risky to specialise too narrowly," Ms Chan says.

Mainstar finds the Internet a very useful marketing tool but also advertises in trade magazines as a way to connect with new customers. Main markets outside of Hong Kong and the mainland are the UK, the US, Germany and Australia.

Mainstar Industries Ltd certainly appears to have current activities fired up to meet demand.



Mainstar Industries Ltd
13/F, Blk A
Hop Ming Fty Bldg
6-10 On Yip St
Chai Wan
Hong Kong
Tel: 852-2558-9319
Fax: 852-2557-6936
Web: www.mainstar.hk
Year Established : 1991
Major Product Categories : ferrite transformers, toroidal chokes/coils, EMI line filters, audio/voice transformers
Brands & Certificate : -
Minimum Order : -
Monthly Production : 5 million pieces
Delivery Time : 30-120 days/日, depends on materials supply
Factory Size & Location :
60,000 square feet ; Zhen Long
Workforce : 300