E-mech switches: still a safe bet

Despite predictions that snap action switches must soon be a thing of the past, sales continue to boom. Distribution sales manager, ZF Switches and Sensors, Mark Mills, explains why.

Consumers and designers of electronic devices and systems love to use the latest technologies, particularly in human machine interface solutions, where it seems that every conceivable system is now controlled by a touch screen or tablet device. This type of product dominates home automation, portable electronic products, industrial control and automotive devices.

These modern technologies are not a universal solution, however, especially for industrial, machine control, security and safety applications. Despite years of rumours that snap action micro-switches would be replaced by cutting-edge technologies, sales of these long-established electromechanical products continue to boom. Why should this be the case in the current age of connected electronic control?

The answer lies in the fact that industrial applications, appliances, white goods, power tools and industrial linear drive markets have specific requirements that cannot be met by electronic switching systems.

Safety first
Primarily, the reason microswitches are still popular is safety. Microswitches can be specified with EN60335-1, a standard for the safety of electrical appliances for household and similar purposes. Battery-operated appliances and other DC powered devices are also within the scope of this standard. Equipment not intended for normal household use, but which nevertheless may be a source of danger to the public including appliances for use in shops, light industry and on farms, also fall under this standard. Examples of such products include catering equipment, cleaning appliances for commercial use and appliances for hairdressers.

Switches in this category also offer installation and use. For example, microswitches can be mounted to equipment or panels in any plane and in harsh environments, with a wide range of actuator options available to simplify system design. Visible actuation makes it easy for installers and service technicians to see at a glance when a microswitch operates, thereby simplifying fault-finding.

With their wide operating temperature range, typically up to 150°C or in some cases 200°C to withstand internal appliance temperatures, they can be specified in extreme environments. In line with this goal, they also offer reliability providing up to 100,000 operations, and the option of a simple, low cost replacement, when required.

Finally, for industrial systems, microswitches boast high current switching with contacts rated up to 30A, as well as isolation advantages. Unlike electronic switching methods, which always have a small leakage current, a microswitch provides a physical disconnection and typically an insulation resistance of 100MΩ.

Future demand
Distribution sales manager at ZF Switches and Sensors, Mark Mills, commented: “ZF had a record year for switch sales in Europe in 2016, and we continue to be the market leader with some 30 per cent market share based on units shipped. Continued increase in demand from key customers, specifically those in the small appliance market has supported the development of sales, while competitor activity has reduced, as many move their focus away from switches.”

So, it seems snap action microswitches may yet continue to be a viable design option for many years to come. Their low cost, wide availability, service life and flexibility make them a component of choice for control and safety switching in consumer and industrial equipment.