Making the Connection in a Harsh Environment
By Lynda Nolen and Arthur Visser, with contributions from HARTING, Schaltbau, and Amphenol

Globally, roughly 44 percent of electronic connectors are used in military/aerospace, industrial, automotive, and transportation equipment. Within these end-use sectors, a specific number of applications fall within the category of “harsh environment.”

However, there is no clear definition of harsh environment in the industry. Some connectors used in harsh environment applications are also used in less severe circumstances. Others are designed to handle specific conditions and are targeted to a limited audience. This makes it virtually impossible to estimate the total market for connectors used in a harsh environment.

Therefore, the best way to survey this landscape is to identify specific applications and connectors on a one-by-one basis and look at specific combinations of applications and connector use. One or more extremities beyond what is considered “normal indoor conditions” usually characterize a harsh environment. These include: 

• High or low temperatures

• Vibrations

• Electromagnetic radiation

• High voltage/current (often combined with other extremities)

• Physical abuse (by users, passers-by, other hardware, etc.)

• Shock

• Mechanical forces applied to the connection (pulling, pushing, hitting, etc.)

• Precipitation (rain, snow, etc.)

• Humidity, fog, and other environmental factors that create an excessively moist or dry atmosphere

• Exposure to chemicals, oils, or other substances

• Corrosion or abrasion (seawater, sand, etc.)

• Pressure (such as sub-sea)

Connectors for use in harsh environments are often designed with a specific purpose or application in mind. On the basis of its intended purpose, the materials, shape, and type of termination are selected, and the necessary approvals are obtained. Some of the variables involved are: 

• Metal and/or plastic housing (chemical composition)

• Termination technology

• Sealing

• Cable glands and tension relief

• Shock and vibration absorption

• Electrical characteristics (current, voltage, and insulation)

• Physical dimensions

Connectors for Railway Technology
Railway applications are one area that is widely considered to be a harsh environment. Connectors for railway applications are often used to connect the power and signal lines of rail vehicles. Depending on the application, their design has to be in accordance with international railway standards for power supply, audio and data technology, and/or emergency brake override. See International Union of Railways (UIC).

IRIS, the International Railway Industry Standard, is an international standard used in the industry “to develop and implement a global system for the evaluation of companies supplying to the railway industry with uniform language, uniform assessment guidelines and mutual acceptance of audits, which will create a high level of transparency throughout the supply chain.” On the IRIS website we find a database of certified companies, and among them we find a range of connector manufacturers and cable assembly makers.

On the customer/OEM side, we find a large group of sub-suppliers, and logically, the manufacturers of railway equipment and rolling stock. Manufacturers of locomotive and rail cars include: 

Among the hundreds of connector manufacturers in the world (see The World’s Connector Companies), we count a select group of manufacturers that have dedicated products for the railway industry and/or target this market with a range of connectors suitable for use in railway applications.

Schaltbau is a German connector manufacturer specializing in connectors for railway applications. Design and development of customer-specific connectors is one of their core competencies. Schaltbau has developed a range of connections that comply with the various industrial international railway standards.

Schaltbau UIC 558 VE Series Connectors
This Schaltbau connector complies with the requirements of UIC 558 VE (up to 1994: UIC 568 VE).

This Class 218 diesel locomotive is equipped with two Schaltbau UIC 558 Series sockets on its front end. The two sockets, with gray lids and red stripes, positioned above the DB logo, are used for jumper transmission of control commands, such as time-multiplex push-pull control, as well as automatic door release, central closing of doors, and control of lighting. These jumpers also facilitate public address announcements and driver/train communication. The rugged design of UIC connectors makes them extra-resistant to chemicals. They also feature a breakaway connection for the non-destructive separation of plug and receptacle when two electrically, not decoupled, vehicles move apart. 

Schaltbau’s UIC 552 series connectors are 1-pole connectors that ensure the power between the motive power unit and the individual passenger coaches. An optional switching element that is integrated in the receptacle is used for feedback, signalling that a plug has been successfully mated.

Flexible Connection in Railway Maintenance Applications
HARTING is another German connector manufacturer with a broad line of connectors for use in harsh environments.

Rail is the single most valuable asset of most railways. Extending the life of the rail by rail grinding is considered the single most effective maintenance practice to control the effect of rolling contact fatigue, restore profile, and maximize value from the rail asset. Loram manufactures rail-grinding equipment that incorporates high power, flexible, grinding modules in configurations ranging from 16 to 96 grinding stones. Communication between the grinding cars is accomplished by a coax-based ControlNet® system.

The HARTING Han-Quintax® is a highly-shielded, low-impedance, 4-pin connector that is assembled into the Han-Modular® frame connector and then assembled into IP65 hoods and housings. In this application, up to eight coax cables can be (dis)connected at the same time. The completely assembled connector has been tested to meet the latest vibration test criteria.
 

Safe Connections Under Extreme Environmental Conditions
In this rail bogie application, connectors are used to transmit revolutions per minute (rpm) and bearing temperature signals at the bogie of the “Blue Tiger” diesel locomotive. Sensors are fitted to the axles in order to obtain information about the correct functioning of the bearings and current speed. Connectors, along with cables, are used with these sensors to transmit the relevant signals to the evaluation electronics. In the event of a fault, quick and safe disassembly is required. The connectors are located externally, so they are constantly subjected to thermal, mechanical, and corrosive ambient conditions, namely heat, cold, vibration, and the impact of stones, salt, etc.

In order to guarantee problem-free operation under these extreme conditions, a HARTING Han® HPR (High Pressure Resistant) connector is selected.

The following features guarantee the connector function:

• IP68 protection

• Use of a non-corrosive alloy

• Internal, protected seal

• Fastening screws within the sealed area

• Locking elements made of stainless steel

Connector Manufacturers and Their Dedicated Railway Products
Other manufacturers have also developed specific connectors for use in railway applications. Following are some links to specific product/application pages related to the railway business 

Amphenol
Deutsch
HARTING
Huber+Suhner
ITT
Multi-Contact
Phoenix Contact
Schaltbau
Tyco Electronics
Weidmuller

Railway Industry Projects
Not surprisingly, there are also plenty of dedicated websites for the railway industry. One of them also provides some detail on upcoming and ongoing railway projects: Railway Technology

Connectors for the Diesel Engine Industry
The diesel engine industry requires harsh environment connectors. Connectors used in diesel engine applications must be able to operate efficiently in an area permeated with diesel and a variety of lubricants, but they must also be able to withstand extreme temperature changes and high vibration. The diesel engine industry has seen considerable improvement over the last decade, from noisy engines and excessive amounts of noxious gases to the quieter, more fuel-efficient engines of today, which release a fraction of the emissions produced by previous diesel engines.

One of the underlying reasons diesel engines have improved over the last decade has been the incorporation of additional functions and systems controlled by the electronic driver and electronic control units (ECU) of these vehicles. One of these systems is the common rail injector. Installed in the engine’s cylinder head and attached by wires to the main engine harness, the common rail injector system supplies multiple injections per working cycle, allowing diesel engines to release just the necessary amount of fuel, at just the right time, in various cycles. By injecting fuel in different cycles, engines run more efficiently and quietly, and have reduced emissions.

Since 1999, Bosch has been a key contributor to the development of the common rail injector system and a manufacturer of common rail injector systems to the commercial diesel market. Although Bosch developed excellent systems, the connection from the injector to the main engine harness, which eventually was connected to the ECU, and supplied the signal to increase or decrease fuel pressure, was never an easy connection. Typically, the two wires sending the information back and forth were wrapped around the threaded posts on the top of the injector and held in place by a captive nut that was torqued down over the threaded post. Although it provided a secure connection to the control unit, this method of connection had its drawbacks. Over-torque the nut and you risk breaking the post or the injector. This doesn’t include the fact you had to make sure you had sufficient clearance to access the nut, or the fact that this method was very labor-intensive and time-consuming. The introduction of a new connector by Amphenol Technical Products International has alleviated many of these problems. Designed specifically for use with the common rail fuel injector for commercial diesel engines, Amphenol’s overmolded push-on connector allows for a quick, easy attachment. Manufactured of engine-grade high-temperature plastic and totally sealed, ”the overmolded push-on connector has a very low profile for tight envelopes, prevents damage to the injector through over-torquing, and saves time, and in turn, labor costs,” said Andy Sleeman, director of sales and marketing. “Theoretically, it also can reduce warranty claims and scrap created by damaged and unusable injectors.” Committed to working with any diesel engine maker wishing to incorporate this solution, Amphenol’s factory-terminated, push-on, full-wire-harness assembly provides a quick and reliable connection in an unforgiving environment.

Oil and Gas Exploration: Downhole Applications
Continually exposed to extreme temperatures, high pressure, chemicals, and sour gas, connectors designed for downhole applications provide critical data to platform operators and service companies, as well as provide the power to sensing equipment. Equipment designed to provide measurement and logging data while drilling—as well as connections to a variety of sensors, including weight-on-bit, flow, bore-hole pressure, and gamma ray sensors—must all have reliable connections in order for the operation to be successful.

Because of the extreme environment these connectors must operate in, connectors used in downhole oil and gas logging applications are generally hermetically sealed connectors, manufactured out of glass, ceramic, or metal composites, like corrosion-resistant inconel, a nickel-based alloy with chromium, molybdenum, and iron. Other options include the use of thermoplastic, like those manufactured by Greene Tweed, using injection molded Arlon® 2000. Predominately found in bulkhead-style, single-pin or coaxial styles, downhole connectors must also be able to withstand unusually rough handling conditions. Utilizing a variety of contact materials, including oxygen-free copper, inconel, and beryllium copper, connectors used in the oil and gas exploration industry are relied upon to provide uninterruptible service in an industry where even minimal downtime can amount to thousands of dollars lost.

Although relatively new to the downhole industry, one of the newest connector types to enter the downhole industry is the fiber optic connector. Designed to withstand the same rigorous environment their copper counterparts must endure, fiber optic connections have been shown to improve real-time data collection and monitoring by as much as 10 times the normal connection. This improvement not only eliminates unnecessary well intervention, but also allows owners and operators to make proactive decisions and increase production from the well.

Bishop & Associates Comments:

• While roughly 44 percent of all electronic connectors worldwide are used in military/aerospace, industrial, automotive, and transportation applications, it remains difficult to estimate the exact volume of connectors specifically designed for use in harsh environment applications. The connector manufacturers’ or OEM’s definition of a harsh environment application often compounds this.

• Although some connectors for use in harsh environment have a broader application spectrum, harsh environment applications tend to be application-specific, requiring specific connector designs. This results in each application/connector combination representing its own niche market.

• Unlike the downturn in the connector market in 2001/2002, the markets for industrial, automotive, and to a certain extent, transportation equipment, are among the worst-hit markets in the economic recession of 2008/2009. This clearly has a negative effect on the market potential for connectors used in harsh environment applications. Though, due to the heterogeneous and fragmented nature of this market, some niches, like harsh environment connectors used in military applications, have performed better than others.

• New technologies, materials, and the use of fiber optic connections improve reliability of connections in harsh environment, significantly reducing the cost of operation or the cost of downtime, therefore, bringing a significant advantage to the industry in which they are used.

• A plus for connector manufacturers who participate in the development and manufacturing of connectors for harsh environment applications is that these opportunities are fairly well “protected” during the lifetime of the equipment. Generally tailored for a specific requirement, connectors manufactured for harsh environment applications traditionally have fewer sources due to the costs associated with design and development.

Arthur Visser Managing Director—Europe, Bishop & Associates Inc. Arthur Visser started his career in 1987 at Océ Corporate headquarters in Venlo, the Netherlands, as a product engineer assigned to provide support to the American Océ organization. In 1988, he joined OMRON Corporation at its European headquarters in the Netherlands as the European product manager responsible for industrial automation systems and components. In 1993, Arthur moved to OMRON Electronics in Brussels as a key account sales engineer, and in 1995 became the product and marketing director. In 1998, he joined the connector manufacturer HARTING as managing director for its Belgian subsidiary. Arthur became an independent consultant, based in Brussels, in 2003. Arthur has a bachelor of science degree in airplane engineering, degrees in marketing and finance, and a master’s degree in e-media enterprising. His native tongue is Dutch, but he also speaks English, French, German, and Russian.

Lynda Nolen Product Specialist, Bishop & Associates Inc. Lynda Nolen has been in the interconnect industry for over 30 years. She has worked in sales, sales management, marketing, and product management for such companies as TRW Electronics Components Group, Sunbelt Components, Cinch Connectors, Arrow Electronics, PEI Genesis, and Delphi Interconnect. Nolen has extensive experience in competitive cross-referencing, drawing, web and catalog review, new product introduction programs, harness and connector assembly programs, account management, and customer service programs. Lynda received her Bachelor of Arts degree from Roger Williams University in Rhode Island in 1979, and has completed various electrical engineering courses.