Application Watch: Enhanced anti-EMI feature priority in time-delay relays for industrial control

China makers of time-delay relays use own R&D, compliance with relevant standards and customization to maximize opportunities in the industrial control market.

As industrial control is the primary market of time-delay relays, makers of the electromechanical component in China focus on designs with strong anti-EMI characteristics for improved reliability and stability. They emphasize the use of high-performance CMOS ICs, which have enhanced EMI immunity, to ensure low power dissipation and a wide rated voltage range, and source the semiconductor usually from foreign providers.

Companies such as Foshan WSK have realized enhanced precision within ±1 percent from such ICs. The company’s AH3-3 model has more than 15 time ranges, which are from 0.1sec to 24 hours. It comes in 12, 24 and 48VDC-rated variants and all are in dimensions of 50x40x57.5mm.

As a rule, local manufacturers follow the required specifications and tests that apply to time-delay relays for industrial applications, including control, automation and signal equipment. They refer not only to the international guidelines detailed in IEC 6181201:1996 but also to the voluntary national standard GB/T 18909.1-2002 to show capability to turn out highly customized but industry-accepted products.

OEM and ODM projects remain a sizeable market for China suppliers, where most derive 30 percent of their businesses. For this reason, customization will continue to drive R&D in the years ahead so makers invest in in-house product development. Relay Industrial International (Shenzhen) Co. Ltd employs a 10-member dedicated team in charge of meeting specific requirements from its domestic and overseas customers.

Industrial control applications account for about 40 percent of shipments of local makers. The sector has been seeing a steady rise in demand in the past several years. In 2017, the majority of companies benefited with a 5 to 10 percent sales growth from this, and the rate of increase is expected to carry over the rest of 2018 and into the following year. Products bound for overseas markets are anticipated to climb at the same rate.

More than half of China’s aggregate output is sent abroad, with Europe, the US, Southeast Asia and the rest of Asia as key destinations. Russia and the Middle East have also been attracting exporters recently.

Encouraged by these projections for the local and international markets, manufacturers such as Relay Industrial are looking to boost production by up to 10 percent.

There are over 200 companies in China’s manufacturing pool for time-delay relays and at least 70 percent are locally owned ventures. The majority can turn out other products for industrial control equipment. All have electromechanical and solid-state relays, and sensors in their catalogs.

Time-delay relays represent between 5 and 30 percent of total shipments. Makers said they are prepared to allocate resources for any increase in orders.

Most factories are in the electronics hubs in Guangdong and Zhejiang provinces, specifically in the cities of Dongguan, Shenzhen, Wenzhou and Ningbo. Many are also in Jiangsu province. There are companies based in central provinces as well.

Mainstream time-delay relays

The typical lineup from China suppliers consists of on-delay and off-delay kinds with a rated voltage of 220 or 380VAC, coil rated voltage of 110, 20 or 380VAC, and maximum rated current of 0.79A at 380VAC. The time delay tolerance is less than 9 percent. Mechanical and electrical life span reaches 1 million cycles.

The main materials and components in manufacturing time-delay relays include coils, ICs, contacts and cases. Most companies obtain these locally or from foreign suppliers, except ICs that are usually purchased overseas and Fuji is among the major sources.

The cost of the inputs rose last year, but the majority of makers kept their time-delay relay prices flat to remain competitive. Others that adjusted their quotes stayed within the 5 to 10 percent range. All rates are expected to stabilize in the months ahead.

The products in this gallery have been handpicked by our China-based market analyst for representing current trends in time-delay relays for industrial control applications from China makers.

Time-delay relay has 0.1 to 999hr range

Relay Industrial International (Shenzhen) Co. Ltd’s model LT3P time-delay relay has an operating voltage of 12, 24VDC, 24, 110, 220 or 380VAC. Its time ranges are 0.01 to 9.99sec, 0.1 to 99.9sec, 1 to 999sec, 0.1 to 99.9min, 0.1 to 99.9hr and 1 to 999hr in A and B functions. Error is ≤0.5±0.4 percent. The mechanical and electrical life span is 100,000 times.

The minimum order is 200 units and the delivery lead time 5 days.

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Time-delay relay with 0.1sec to 10-day range

The MTR 2AR model from Wenzhou Onkak Impex Co. Ltd is a time-relay delay with time ranges of 0.1 to 1sec, 1 to 10sec, 6sec to 1min, 1 to 10min, 6min to 1hr, 1 to 10hr, 0.1 to 1 day and 1 to 10 days. It has a rated voltage of 12, 24VDC or 24 to 250VAC, with voltage tolerance of -15 to 10 percent and respective power consumption of 0.15, 0.3W and 0.4VA. The rated frequency is 50/60Hz in DC.

Order quantity is negotiable. Delivery takes 7 days.

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Time-delay relay with 0.1sec to 999hr settings

This time-delay relay from Wenzhou Zhengyuan Electron Co. Ltd, JS14P model, has time ranges of 0.1 to 9.9sec, 1 to 99sec, 0.1 to 9.9min, 1 to 99min, 0.1 to 99hr, 1 to 99hr, 0.1 to 99.9sec, 0.1 to 999sec, 0.1 to 99.9min, 1 to 999min, 0.1 to 99.9hr and 1 to 999hr.

The CE-approved unit operates in 24, 36, 110, 220, 240 or 380VAC 50/60Hz, 12 or 24VDC. The (resistive) contact capacity is 5A at 220VAC. Dimensions are 84x47x112mm.

The minimum order of 1,000 units has a 25-day delivery lead time.

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Time-delay relay has 24hr range

Yueqing Zhongfa Relay Co. Ltd markets the model SNY161h time-delay relay with a 24hr time range. The contact capacity is 16A at 220VAC.

The unit has ≤50mohm contact and ≥100mohm insulation resistance. It operates in -40 to 55 C. The electrical and mechanical life spans are 100,000 and 10 million times.

The negotiable order quantity can be delivered within 7 days.

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