Innovation in relays to meet needs of new applications

A relay is a remote switch controlled by a current, magnetism or temperature. It is a very sensitive part in any application and should meet stringent quality norms. It is categorised as a safety or protective component because the failure of a relay can result in fire. Relays play a vital role in every electronic instrument or appliance and no circuit is complete without it. The performance of a relay will depend a lot on the raw materials selected.

The growth in the field of electronic relays is, therefore, directly related to the growth of the electronics industry in India. From the manufacturers’ point of view, if the output of electronics product increases, so will the volumes of relays.

By Sandhya Malhotra

Saturday, December  31, 2013: In India, the scope for business in relays is increasing mainly because of the growth in automation projects. By and large, segments like power electronics, consumer electronics, telecom, automotive electronics, industrial instrumentation and controls, test and measuring instruments, defence and aerospace applications, and medical electronics are propelling the growth of the relays domain by leaps and bounds, currently pegged at a 20 per cent increase in volume, year on year.

Worldwide there is an acute shortage of relays. The volumes required have drastically gone up, resulting in long lead times. Moreover, the prices of relays have shot up due to an increase in raw materials and labour costs. As per industry estimates, there are more than 350 branded manufacturers of relays, globally.

What’s new in the market?

Relays are basically electrically operated switches that come in many shapes, sizes and power ratings, suitable for all types of applications. There are many different types of relays such as solid state relays, monitoring and measuring relays, reed relays, MIL, SIL relays, SIP, electromechanical and mechanical relays, etc.

The most common and widely used type is the electromechanical relay or EMR. One of the main disadvantages of an EMR is that it is a mechanical device and it has moving parts. Over a period of time, these parts will wear out and fail, or contact resistance through constant arcing and erosion may make the relay unusable and it will, therefore, need to be replaced. The EMR has been rapidly replaced by solid state relays (SSRs), which provide a high degree of reliability, long life and reduced electromagnetic interference (EMI). These SSR relays don’t have arcing contacts or magnetic fields, and have a much faster response, compared to the conventional electromechanical relay.

Shiv Shankar Singh, vice president, marketing, Rabyte Electronics Pvt Ltd, says, “In India certain applications like Inverter/UPS, EPABX, etc still predominantly use EMRs, the segments of automotive, telecom, industrial applications is driving the growth of new technological innovations in relays with solid state technology. SSRs have advantage over EMRs due to higher reliability and longer life and delivers better performance. SSRs are typically smaller than EMRs savings space on PCB, have no contacts or moving parts to degrade,  provide improved system life cycle costs including simplified designs with reduced power supply and heat dissipation requirements and also available in SMTs which means further miniaturisation, better reliability and performance.”

The market for solid state relays is still at a very nascent stage but may overtake the conventional relays in the coming years. Another emerging type—photomos relays are also gaining ground, though there are not that many applications for these yet.

Electromechanical sugar cube relay, normally 7A-10A ratings, is widely used in many applications like inverter/UPS, stablisers, industrial applications. High capacity inverters/UPS uses higher rating relays of 20A, 30A, 40A, 80A etc. Rabyte offers wide range of relays like electromechanical, solid state, automotive and photoMOS etc,from 0.1A to 80Amp ratings.”

According to R A Gotur, director, India operations, Hongfa Electroacoustic Co Ltd, “Another innovative relay is the latching relay, which operates like a normal relay, that it, it closes when a jolt of current passes through the coil. In this type of relay, the switch stays closed until another pulse to the coil opens it. This saves electricity when continuous operation of the relays is required.”

Rupali Jadhav Menon, CEO, Satronix (India) Pvt Ltd, a largest and widest range of SSRs manufacturer inIndia, says, “Our latest SSRs come with an integrated heatsink; the ceramic substrate is mounted directly on the base of the heatsink. Also, physically their dimensions have changed and for lower ratings they are available in sleeker widths, thereby taking less amount of space in panels/products.

Moreover, relays have come with more value added options such as high voltage, high current DC relays for DC applications such as heaters, lighting and motor controls. The latest trends also include incorporating microprocessors in the relays, especially for heating applications.”  Madhav R Badsheshi, DGM, business development, Electronic Relays India Pvt Ltd, a manufacturer of solid state relays, says, “The construction of SSR is different from EMR. The price of SSR is three times higher than EMR. But it is very economical over a period of time as its reliability is very high compared to the EMR.”

Companies are also constantly developing new varieties of relays as the needs of the industry are changing fast. Another quickly evolving type is the microprocessor based numerical relay with a communication facility. Low profile industrial relays, flag indicating industrial relays with spade terminals, mini sealed PCB relays, low profile plug-in automotive relays, hermetic sealed MIL grade relays, MOSFET and transistor driven relays, and automotive high power relays are very much in demand, says P Lakshmi Devi, DGM, marketing, O/E/N India Ltd. Established in 1968,

O/E/N is one of the leading players for electromechanical components. It has manufacturing plants located in Cochin and Bengaluru, with over 11,000 sq m of factory space.

What key players offer

Hongfa, a Chinese company, is a leader in power, automotive and telecom applications. It is also a leading manufacturer of sugar cube relays. The company produces more than 160 series of relays with more than 40,000 standard specifications. It has an annual production capacity of 1 billion relays. Hongfa has always given top priority to quality and has been awarded all international approvals on quality. Hongfa’s main products are latching relays for metering applications, hermetically sealed relays for defence and aerospace applications, SSRs and power modules, relay sockets, electronic TACT switches, micro switches and metal domes. For a few series of Hongfa’s automotive relays, the lead time is around 54 weeks because of the greater demand.

To improve the quality of relays, Satronix has reduced the human interface in the assembly and test phases. Surface mount component pick-and-place machines, solder reflow ovens and automated test equipment were introduced into production lines to facilitate this requirement. New concepts and equipment for evaluating the integrity of the SCR assembly and measuring thermal efficiency have been adopted to ensure overall quality and reliability.

The manufacturer has also introduced DBC technology. The thermal impedance of DBC is lower than the traditional thick film substrates due to the spreading effect of the copper and the fusing of the traces to the ceramic during the manufacturing process. “The combination of DBC technology and a thinner substrate furnishes the market with SSRs that has an unparalleled thermal efficiency. Effectively managing the base plate temperature on a thermally efficient SSR through the use of adequate heat sinks and controlled ambient air, keeps the SCR die cool and enhances overall system reliability,” says Menon.

Tara Relays offer power relays with chassis mounting. This is available in both opaque low cost and transparent PC dust covers. The company also claims it is one of the Indian manufacturers of ‘T’ type relays, which it has branded as the J P series. This comprises heavy duty PCB mounting power relays, with a switching capacity of 30A at normally open and 20 A at normally closed position. “Our JP series relays are of international standard and very economical. They are available in both open type as well as epoxy sealed versions. Among the PCB mounting relays, the RK series is the most dependable compact sugar cube relay. With a rating of 7A and being epoxy sealed, it has a quick ‘operate and release’ time. This relay is found in the most wide array of applications,” says Kunal Supnekar, director, Tara Relays Pvt Ltd.

Miti Associates has power relays ranging from 25 amps to 150 amps with a high current and long life, and other variants include panel mounting, telecom and PCB power relays. B Ashok Kumar, vice president, marketing, Guardian Group of Companies, a leading manufacturer of various automotive, MIL grade, power and industrial relays used in different applications claims, “The vast majority of landline telephones operating in India work on Guardian relays.

The quick response from the telephone exchange as we pick up a phone happens because of the switching of the telecom relay. In fact, the only moving part in a modern landline telephone exchange is the relay. The types of exchanges operating in our country are RAX, MAX, E10B, etc.”

Rabyte Electronics is a leading electronic components (both active and passive components) distributors and design solutions provider in India for over last 25 years. It represents  over 40 world class principle.

For Relays, Rabyte Electronics is authorised distributor for Japan based Panasonic Electric Works and Taiwan based Rayex Electronics Co. catering to various applications needs of inverter/UPS systems, telecom, industrial electronics, consumer electronics and automotive industries.

Innovations in relays

“With every electronic product undergoing continual technological changes, relays are also witnessing innovations. Relays have become relatively smaller in size and more cost effective, with longer life, higher dependability and capacity,” says Supnekar.

With the advent of new technology the old EMRs are being replaced by the semiconductor or SSRs and numerical digital relays. “The current market share of relays in the electronics market has increased substantially and is going up day by day as machine manufacturers are using them for their edge over mechanical and traditional EMRs. However, automation integrators who have switched to SSRs have to take care of the thermal management factor by using the appropriate heat sinks and cooling measures like force cooling,” points out Menon.

In keeping technological changes and the growing demand in the automotive and telecom industry, relays have undergone major changes, becoming smaller, yet acquiring higher performance ratings. “Besides adding innovation, we also have to work aggressively on controlling costs, since commodities like copper, silver and other precious metals, which are extensively used in relays, have become very expensive. But buyers are not prepared to fully absorb the consequent increase in prices. This calls for innovative value engineering,” says Devi.

Broadly, innovations in relays are going on in four main areas—the first is contact resistances of relays. There is constant focus on finding new materials and coatings for the contacts, which reduce contact resistances. This includes research into complex metallic alloys and surface coats, which is of particular significance in low power relays where one cannot afford contact losses. Second, there has been innovation in how to reduce consumption in coil power. Innovation here is focused on improvements in magnetic characteristics and polarisation of fluxes. This is to reduce both power wastage and undue heating. A third front involves arc management. Innovation in this field is again directed at finding complex alloys that can withstand repeated arcing at the contacts with minimum deterioration. The fourth innovation is improvements in contact bounce and debounce. In this area of material research, there is a continuous emphasis on finding consistent spring material, which minimises bounce and debounce.

Gotur says, “Some of these innovation initiatives, individually and all together, contribute to improved performance, low power losses, and also contribute to the worldwide drive towards green products. Apart from these technology areas, Hongfa is constantly striving to expand its product line and meet the requirements of new application areas such as photo coupled, transformer coupled and hybrid solid state relays.”

Moreover, protective relays have also seen tremendous technological innovations. These are a vital part of switchgear equipment. The function of a protective relay is to initiate a signal to circuit breakers for disconnecting the element of the power system when it develops a fault.

Yuvraj Samal, manager, International Business, JVS Electronics Pvt Ltd, a manufacturer of static, numerical and communicable and electromechanical relays, says, “Over the last two decades, there have been rapid developments in relay technology. The most important advancement has been due to the advent of computer technology, which has helped in the development of numerical relays. Various technologies like electromechanical, static, microprocessor, micro controller based and numerical technologies are in place. Although all these technologies are presently in use, numerical relay technology is gaining popularity over others, due to its communication and intelligent capabilities, which facilitate integrated control, protection and metering features.”

“Miniaturisation is taking place in the field of relays as in the case of other components, due to the requirement of compact and smaller parts for assembly of PCBs. Cost reduction is a continuing process across the industry, with many going in for automation and optimum utilisation of manpower and machinery,” Kumar says

Buyers’ requirements

There are several types of relays that are currently available in the market. Buyers’ needs vary with regard to application, delivery schedules, price competitiveness, quality and compatibility. “Buyers should also keep abreast about technology, be careful in the selection of genuine products, fine tune their price negotiating skills, identify the right manufacturers and services, etc,” says Singh.

There are two specifications that you must consider when selecting a relay for use in an automobile—the coil voltage and the current carrying capability of contacts. Some relays have different current ratings for NC contacts and the NO contacts. Hence, if you need to pass significant current through the NC contacts, buyers should check the manufacturer’s specifications for the relay.

“There are several low cost and spurious options available. Therefore, when selecting a relay for the first time, make sure you are buying from the original and qualified suppliers,” says Amarjeet Singh, proprietor, BR Industries, a small scale manufacturer of electromagnetic relays that also produces its own plastic backalite and sheet metal components.

Buying tips

Buyers should look at the pedigree of the product. Today, buyers are faced with a flood of low priced Chinese products in the market. “The buyer should check whether the product is genuine and whether the manufacturer has the ability to support the product with applications engineering, technical support and documentation, especially on test and inspection standards. Otherwise, the buyer may save a few rupees today but repent the decision later when faced with quality issues that would have severe and disproportionate cost implications,” says Devi.

“Each buyer’s requirement is different. Today the buyer’s basic criteria for selection, apart from the type of relay, is the international safety standards like CE for Europe and UL if exporting to USA. These international markings are based on relevant IEC standards applicable to a particular kind of relay,” says Menon.

Supnekar is, however, concerned over the low awareness levels among consumers. Relays face competition from cheap and affordable technologies, which customers are not aware of. They should do some research and learn about the latest technologies to avail the best in the market. The buyer must deal with a technically competent supplier, who can assist him in choosing the right relay and can understand the customers’ application.

Devi emphasises, “Our advice to buyers is to audit and qualify the relay supplier so that it will be worth it in the long run. Moreover, buyers have to understand that relay manufacturers are facing the impact of a spiralling rise in the cost of raw materials like copper, silver and other precious metals, which are used extensively in relays. While relay manufacturers are obliged to work aggressively on controlling overall costs to compensate to some extent for cost increases, buyers have to be prepared to, at least partially, absorb the consequent increase in prices.”

Mihir Shah, director, Miti Associates, says, “Before buying relays, buyers should check the quality, test certificates of products, product approval from industries, price competitiveness, product delivery schedules, service options, durability, quality control certification and accreditation.

Says Gotur, “Buyers should consider manufacturing dates, batch codes, on time delivery, background of distributors and payment terms, while buying relays from traders. They have to ensure that they are getting the right quality with zero defect parts, at the right price at the right time, with proper packing.”

It is very important to buy from authorised distributors, since fake relays are available in the unorganised market. “We not only provide the right product to the customers, but also offer a one year standard warranty on relays. Customers should understand that a relay is a protective component and it has to be of high quality,” says Singh.

Service support

Relays come under the engineering products category. Moreover, not all buyers are technically knowledgeable. Since the upgradation of technologies is continuous, to keep pace with the latest developments is difficult. “We conduct seminars and product awareness training programmes (both on site and off site), depending upon the customers’ choice, by participating in technical exhibitions, furnishing technical details on our website, and providing after sales service,” says Samal.

O/E/N offers total applications engineering support and helps the buyer select the most cost-optimised relay solution. Its field sales engineers provide personalised support depending on each buyer’s needs. The firm’s network of distributors, stockists and dealers are spread across the country and provides professional support, apart from offering after sales and warranty support.

Supnekar says, “Our service support starts with first understanding the customer’s requirement, suggesting improvements and offering alternatives in their applications. Our service team ensures continuous follow up with the customers for any problems or suggestions they may have. Being a manufacturer, we assure full replacement of any goods rejected in rare cases of manufacturing defects. In all these ways, we see to it that our service support completely satisfies the customer.”

Kumar informs, “We get less than 0.1 per cent of customer complaints and we offer a two year warranty for our products. We also offer free replacement, and take immediate action on customer complaints and avoid repeat complaints.”

Types of relays

• Electromechanical relays have a moving plate with contacts on it, while solid state relays work similar to transistors and have no moving parts.
• Power relays use an electromagnet to move a set of contacts. The contacts are pulled towards the electromagnet while current is flowing in it. These contacts are connected to a spring that pulls them back when the current stops flowing.
• Latching relays act like a two-pole switch in that the contacts stay in position when the current stops flowing. This is achieved by using a solenoid to move a ratchet and cam, or by using an electromagnet on either side.
• Reed relays have only a set of ferro-metallic contacts inside a glass tube. The contacts close when an external magnetic field is applied, and open again when it is removed. Reed relays are commonly used as door sensors for alarm systems.
• Overload relays are similar to reed relays but use a bimetallic strip to move the contacts. High temperatures cause the strip to bend, bringing the contacts together.
• Automotive relays: These relays are mainly used in passenger cars and commercial vehicles. The general applications for these relays are in automotive flashers, wiper controls, head lamp relays, horn relays and wiring harness applications.
• Signal/Telecom relays: Landline telephones operate on relays. The quick response from the telephone exchange when the phone is picked up occurs because of the switching of the telecom relay. In fact, the only moving part in a modern landline telephone exchange is the relay.
• Power and industrial relays: Various types of industrial and auxiliary relays are used in power generation plants and other industrial controls.
• Hermetic relays: Hermetic sealed MIL approved relays are used in defence, navigational/communication equipment, aircraft, and in areas where environmental conditions are severe.

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