Relays have not undergone much change

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An important part of almost all electronics power products,relays cater to sectors like automotive, mechanical, defence, telecommunications, medical, instrumentation or industrial. Relay is an electrically operated switch and its property to activate and deactivate circuit on the basis of another circuit has increased its demand in this era of value addition. They help in designing equipment that can run various circuits like in the case of automation.

By Himanshu Yadav

Thursday, October 15, 2009: A relay offers multifarious advantages when it comes to electrical products. For that matter they have more or less replaced transistors as the premium mode of current switching. If we compare the two, the differences and the advantages of relay over transistors will appear striking. So keeping in mind the overall factors and the growth noticed in sectors like telecommunications, automotive, information technology, relays require a considerable rise in terms of local production. Also, considering the scenario of electronic component manufacturing, domestic relay production will also have to face stiff competition from the imported ones.

Rise in demand

The current market for relays in India is encouraging and growth prospects seems to be much higher than in any other sector as its demand is rising. According to industry sources, the market for relay in India is over Rs 100 million. The two main types of relay that dominate the market are electromechanical and solidstate. While experts feel that solidstate relays will see high growth rate in the years ahead, electromechanical relay growth will be expected in telecommunications, automated test equipment and auto­motive markets. Power conditioning sector has the maximum demand. Besides industrial equipment, office automation, business machines are the other sectors observing high growth rate.

Yuvraj Samal, manager, JVS Electronics Pvt Ltd, shares on the growth aspect, “On a worldwide basis the annual market for medium and high voltage protective relaying products and equipment currently exceeds $1 billion. As far as Indian market is concerned the growing demand of electricity will give rise to huge potential market for protec­tive relays.”

Buyer’s preference

Market trends in India points to slow but steady shift towards branded relays. This brand preference in Indian customers in the last decade has given boost to the distributors who opted for relays of reputed companies. “More than 70 per cent of customers prefer branded relays,” says Samal. The market has evolved tremen­dously and customers are conscious about quality and standard of the products. Now customers look for quality certification of the products and lay emphasis on after sales services.

As shared by Kishor Vithalani, proprietor, Shreeji Semiconductors, “Today customers are more aware and want quality products along with right service support. Local players can utilise this point in combating the competition faced by the imported players.”

Price is another factor that guides buyer’s decision. The zero custom duty on the component leads com­panies to source components from abroad than from local manufacturers. Sadanand D Nayar, manager, Vital Electronics and Manufacturing Co., manufacturer of PCB assemblies, says, “To get the maximum benefit of reliability, price and quality, we prefer sourcing from outside the country, plus there is zero custom duty. In terms of design, foreign products excel over Indian ones.”

BuYing Tips

  • Check quality, type, test certificates of products
  • Take product approval from indus­tries
  • Check price competitiveness
  • Check product delivery, service and durability
  • Check complete technical suitabil­ity of the relay type chosen to the application intended
  • After verifying the requirements check for load consideration with the manufacturer

Purchasing factors

Although customers are aware about their requirements, there are certain points which needs to be taken care of while doing a pur­chase for relays. Customers who are not much aware of brands or how to select the right brand, Vithalani suggests they look for quality cer­tifications that relays have. “All companies using various types of relays before sourcing relays must verify whether the desired product is manufactured as per interna­tional standard and has the neces­sary certifications such as UL, TUV, CUR, CQC,” says Vithalani.

Madhav R Badsheshi, DGM, busi­ness development, Electronic Relays India Pvt Ltd, points out, “It is always advisable to verify the requirement of a particular application—whether it needs a solidstate relay or can be done with the inexpensive electro­mechanical relay. Once it is done then load considerations are very important, which has to be discussed with the manufacturer before buying the product.”

Kunal Supnekar, director, Tara Relays Pvt ltd suggests, “while pur­chasing relays, customers should embrace at least a mid-term policy if not a long-term one. The consist­ency of quality, price and delivery should be given priority. Ensuring the complete technical suitability of the relay type chosen for an application is important and can define technical success of the end product.”

Another important point that needs to be kept in mind during purchase is comparative analysis. “Comparing only one criteria, like say price or quality should be avoided and the overall value package should be considered for a true comparison,” further adds Supnekar.

Relay vs transistors

RELAY

  • Relay can switch AC & DC
  • Relays can switch high voltages
  • Relays are a better choice for switching large currents (>5A)
  • Relays can switch many contacts at once

TRANSISTORS

  • Transistors can only switch DC
  • Transistors cannot
  • Transistors cannot

New technology

Relay technology is now 40-year-old and has not undergone any major changes except for the the high cur­rents and miniaturisation. This is due tothefactthatR&Dhasbeingtotallyne­glected by the manufacturers. But now most relay producers in India are spending a significant percentage of their revenue to upgrade their tech­nologies.

Says Samal, “With the advent of new technology the old electrome­chanical relays are being replaced by the semiconductor or solidstate relays and numerical digital relays, where miniaturisation, standardisation, reli­ability and price competitiveness are dominating.”

Relays that dominate the market

Electromechanical relay: Electromechanical relays are perhaps the most widely used relays in automated test equipment applications. They support a wide range of signal characteristics, from low voltage/current to high voltage/ current as well as from DC to GHz frequencies. That is why an electromechanical relay is always available with signal characteristics that match the given system requirements. Electromechanical relays are used in a wide variety of switch modules. While their robustness makes them well suited for many applications, particularly where switching speed is not the highest concern, their versatility makes them compatible to all types of switching configurations including general purpose, multiplexers, and matrices.

Reed relays: Reed relays, like electromechanical relays, have physical contacts that are mechanically actuated to open or close a path. The contacts in this case are, however, much smaller and lower in mass than those used in electromechanical relays. The small size and high speed of this variety of relay make it a great choice for many switching applications.

Solidstate relays: These are a faster alternative to electromechanical relays. Their switching time is dependent on the time required to power an LED ‘on’ and ‘off’—approximately 1 millisecond and 0.5 millisecond, respectively. Since they are devoid of mechanical parts, life expectancy of solidstate relays is higher than an electromechanical or reed relay. Solidstate relays are not as robust as electromechanical relays. Much like reed relays, they are highly susceptible to surge currents and damage when used at signal levels above their rating. They are the most commonly used relays in matrices and multiplexers. The automation and control and machinery industries are the major buyers of solid state relays. Whereas, the coming years would see the demand for solidstate relays coming from textile, sugar, and chemical industry.

Apart from the above mentioned relays, the market is opening up for high frequency switching relays, too. These are already being used in the telecommunications industry, but they are also set to play an important part in the defence sector in the coming years.

Electronics Bazaar, South Asia’s No.1 Electronics B2B magazine

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