Tech Tips: Selecting DC Relays & Microswitches for Safety in Electric Mobility by Omron 

With the advent of pervasive electric mobility, design issues related to greater safety, energy efficiency and functionality are also increasing. Electronic components maker Omron has prepared a thoughtful guide on the selection of DC relays and microswitches supporting safety control. The multi-level guide provides universal perspective on the subject and coordinates to its continued development of products addressing the challenges. A research-oriented company, Omron counts certain magnetic technologies such as arc plasma control and electromagnetic sensing among its special core competencies. 

 
DC relays and microswitches suitable for electric mobility are components that can stably energize and interrupt DC loads even under vibration and shock. Furthermore, the low power consumption and small size of these components will make them more valuable for mobility. Therefore, it is important to select these components from the three perspectives: stable energizing and interruption; low power consumption; and miniaturization, explains the company. 

Selection points for components to address engineers’ concerns 

In electric mobility, design issues include stable energization and interruption of DC loads to have stable electric control, realization of low power consumption drive for high energy efficiency, and miniaturization and weight reduction of mechanisms to achieve both design and functionality. 
The following three points need to be considered for selecting DC relays and microswitches to solve each problem. 

  • (1) Ability to energize and interrupt DC loads stably even under vibration and shock conditions 
  • (2) Eliminating wasteful power consumption 
  • (3) Thoroughly small in size 

With these factors in mind, Omron quantifies and grades its various solutions accordingly. Among recently developed products that apply are several new power relays and switch devices. 

The new G9KB-1A-E power relay with bidirectional switching has a capacity up to 600 VDC, 50A, in the standard model and 800 VDC, 100A, in the high-capacity model. 
G9EJ-1-E power relays are compact DC power relays capable of switching 400 V 15 A DC loads. They actualize a high-capacity interruption through the function of extinction of magnetic arc by adopting a high-efficiency magnetic circuit. 
Coming soon from Omron is the G9EK power relay rated at 500 VDC/120A. 

Arc plasma control and electromagnetic sensing are core competencies

Arc plasma control is counted by Omron as one of its core competencies, providing safe DC current breaking technology with investigations of complex arc plasma phenomenon and mechanism. The company has developed original simulation technology to visualize complex arc plasma behavior, accomplishing quantification of transient physical properties such as metal vapor and electrical conductivity that can be difficult to measure. The analyses have led to designing safe DC high voltage and current breaking devices. 

Electromagnetic field sensing is another, involving sensing technologies that use radio waves, magnetic fields and electric fields invisible to the human eye​. 

Proximity sensing detects metal at a distance using a resonated coil, depicted at left, while capacitive sensing detects the position of objects or of construction wood behind walls by measuring the capacitance, and impulse radar is realized using high-frequency design technology. 
For proximetry sensing, a metal sensing device using coils can detect the position of iron bars in concrete. By measuring the energy required for resonance, it detects with high resolution reinforcing bars in deep positions. 

For more info and to view the complete presentation, see www.omron.com