Miniaturization efforts continue despite makers’ strong emphasis on traditional designs.

The miniaturization trend continues to pick up pace in China’s power transformers industry even as traditional models remain dominant. Development work is ongoing for planar, chip and thin-film types, although it is mostly the large enterprises that offer these new variants. Nevertheless, more makers are planning to boost output of small and lightweight versions in the years ahead. Many companies also concentrate on units with high frequency and low power consumption.

	Gangyuan's model EL19070308 power transformer has 90 to 264V input and 3 to 12W power output. It is UL94V-0-rated.

Homegrown enterprises leverage product maturity and labor-intensive manufacture to meet rising demand despite material and manpower cost challenges. They also emphasize in-house capability to meet customization requirements.

The current selection in China caters mainly to the household appliance, communications, and consumer, automotive and medical electronics sectors. These are expected to sustain strong demand, especially the first two in the domestic market, thanks to the national government’s Consumer Electronics Subsidy Program and 3G network projects.

Enterprises also hope to benefit from climbing orders from the LED lighting, LCD monitor, HDTV and portable electronics segments. The first, in particular, is gaining steam, buoyed by the energy conservation trends.

There are about 2,200 makers of power transformers in China, more than 70 percent of the country’s manufacturing base for transformers. The majority of the companies are based in Guangdong, Zhejiang, Jiangsu and Fujian provinces, and Beijing and Shanghai. Locally owned operations represent half of the pool. In coming months, the supplier number is expected to decrease due to intense competition in the low end and climbing raw material costs.

Even so, China will remain the world’s largest sourcing hub worldwide for this line with a share of global output exceeding 20 percent. Gangyuan Electric Co. Ltd projects over 15 percent output growth by year-end and 5 percent for exports, with the latter doubling in 2012.

	The YL-48-1001000B model from Dongguan Yinli boasts more than 75 percent efficiency.

Power transformer selection

Manufacturers categorize power transformers by shape, core, winding, phase and cooling method.

Based on shape, there are ring, EI, R and C kinds, with the first two making up the mainstream.

The ring version is widely used in electronic products, and communication and medical systems. It has low magnetic leakage and noise, and shares high efficiency attributes with the C variety. The last, which also boasts elevated magnetic flux density, is employed in home appliances, electronic equipment and instruments.

EI models have an anti-windup function and are typically adopted in driver transformers, switching power supplies, UPS, TVs, AC/DC adapters, computers and other electronic devices.

By core configuration, releases are classified into C, amorphous alloy and shell-type varieties. There are also 2, 3 and auto-winding, and single- and 3-phase units.

In terms of cooling method, dry and oil-immersed are the options. The former versions are mainly utilized in lighting systems and electronic circuits.

Dongguan Yinli Electronics Co. Ltd specializes in the EI type with reduced frequency. Units below 30W dominate its selection, which comprises pin, lead-wire and encapsulated variants.

Gangyuan offers PQ, EBY, EI, EE, EER, EEL, EC, EF, TB, TL, AR, DR, UU and THV configurations. Its high-frequency kinds come in 10 and 100W ratings. The main applications are TVs, PCs, and MP3, MP4 and DVD players. Products are also suitable for audio systems, communication devices, medical equipment, household appliances and electronic instruments.

At Hangzhou Yukingda Imp. & Exp. Co. Ltd, there are 50/60Hz versions in EI, encapsulated and toroidal configurations. Its FBH-15 to 500 Series consists of single-phase units with 80 to 200VA capacity. These are available in various AC input voltage ratings to match requirements in different countries. The output counterpart follows custom specifications. The transformers have 50 to 94 percent efficiency, 4 to 19 percent voltage regulation, 0.5 to 10W output no-load loss and below 85 C temperature rise. These comply with CE, RoHS and UL guidelines.

Ningbo Zhongce E.T. Electronics Co. Ltd’s high-frequency selection consists of 15, 30, 75, 100, 140, 150 and 300W units. The components suit telecom, industrial control, automotive and heavy equipment applications.

Ferrite, copper wires and cold-rolled grain-oriented silicon steel sheets are the key materials used in making power transformers. The last is adopted in low- and intermediate-frequency types. High-rated models employ mostly ferrite cores. Combined, these inputs account for about 70 percent of total costs.

Outlay for materials rose by 15 to 20 percent last year, and is forecast to jump by 10 to 15 percent. In particular, rates for silicon steel sheets are projected to climb by 15 percent due to a supply shortage worldwide. At present, the only local provider of the input is Wuhan Iron & Steel. If the situation persists, the increase can touch 20 percent by 2012.

Under efforts to reduce outlay and keep prices stable, some makers are adopting alternative materials such as copper-clad aluminum enamel wire. The input increases the component size but pushes down quotes by 15 to 35 percent, said Hangzhou Yukingda. Gangyuan also employs the wire type.

	Li Tone’s mode RM Type Power Transformer suits switching power supplies, lighting, machinery, telecom and medical equipment, home appliances.

Taiwan: Switching, SMD units dominate line

Switching and SMD units constitute the key categories in Taiwan’s power transformers sector, reflecting makers’ emphasis on better efficiency and further miniaturization. Trends in the latter type point to high frequency but low ferrite core loss and small footprint. Computer and telecom products, LED lighting, monitors and TVs are the major applications, with the last three the fast-growing markets.

Releases come in toroidal, EI, EE, ER, EF, ETD, EP, PQ and RM variants based on core and structure. There are high- and low-frequency models. The latter consist of lamination versions for home appliances such as air conditioners and refrigerators, electric tools and equipment, and handset chargers. High-frequency kinds are suitable for computer and telecom products, but are finding use in more home electronics. The last is expected to drive shipment growth further and secure the type’s majority share of the island’s total delivery volume for power transformers.

Most Taiwan suppliers operate factories in mainland China to take advantage of lower costs there for the labor-intensive line. The strategy also brings them nearer to major clients, generating additional savings on transportation and facilitating delivery of aftersales service. To counter the current spike in labor expenditure in the mainland, some companies are moving manufacturing activities inland and boosting automation.

In addition to power transformers, Taiwan makers offer inductors, and switching and AC adapters under efforts to provide a one-stop sourcing solution for power inverters and supplies

Product gallery Dongguan Bohan Electronics Co. Ltd (mainland China) Model: 005 Description: EP type, magnetically shielded, multiple output optional; EFD type, multiple output, horizontal installation, for low-power switch transformers

Goldsphere Industries Co. Ltd (Hong Kong) Model: GS-EER-28 Description: High frequency, reliability; custom designs available; OEM/ODM orders accepted

Hangzhou Yukingda Imp. & Exp. Co. Ltd (mainland China) Model: EI02 MOQ: 2,000 units Description: Single-phase; 0.5 to 120VA capacity; 110 to 120V and 220 to 240VAC input, 50 or 60Hz; 10 to 15% voltage regulation; class B insulation; 95 C temperature rise; for electronic meters and apparatuses, cable TVs and digital networks, electronic controls, medical equipment

Lion Electronics Enterprise Co. Ltd (Taiwan) Model: EE65 Description: 500W maximum power output; 15 to 200kHz frequency range; class A or B insulation; UL94V-0 or UL94V-1-rated; for flyback, forward, push-pull and bridge circuits; UL, CSA, VDE

Ningbo Zhongce E.T. Electronics Co. Ltd (mainland China) Model: MT-2-A Description: 120, 208, 240, 277 and 480V, 50/60Hz primary, 24V secondary input; 50, 60, 75, 96W power output; 3,500V rms hipot dielectric strength; class B insulation; UL 1585, UL 5085-3, CSA 22.2 66.3, EN 61558

Note: This article "Compact units advance power transformers line" was originally published by Global Sources, a leading business-to-business media company and a primary facilitator of trade with China manufacturers and India suppliers, providing essential sourcing information to volume buyers through our e-magazines, trade shows and industry research.

All price quotes in this report are in US dollars unless otherwise specified. FOB prices were provided by the companies interviewed only as reference prices at the time of interview and may have changed.

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