OMRON Electronic Components Europe has expanded its relay portfolio with the launch of the G9KJ, a compact board-mount device designed for pre-charge circuits in high-voltage applications. The relay is rated for DC link voltages up to 1500V and is intended for use in energy storage systems and electric vehicle fast chargers. By replacing larger contactors, the component can reduce system size, weight, and bill of materials.
Pre-charge circuits play an important role in high-voltage power electronics. They limit inrush currents when a system starts up, protecting components such as DC link capacitors, main contactors, and protection circuitry from electrical stress.
Role of pre-charge control in high-voltage systems
When energy storage systems or fast chargers begin operating, large capacitors within the power stage must be charged. If this happens instantly, the sudden surge of current can damage equipment or trigger protection systems that interrupt operation.
Pre-charge circuits address this issue by routing the initial current through a resistor. This reduces the electrical stress on the system while allowing the capacitors to charge gradually before the main current path is engaged.
OMRON’s G9KJ relay is designed to act as the switching element in this stage. With a 25A make current and a 5A carry current rating, the relay is suited to the short-duration switching required during pre-charge operation.
Replacing contactors in compact designs
Traditional pre-charge designs often rely on electromechanical contactors. These devices are typically larger and heavier, and may require additional mounting hardware and wiring within the system.
The G9KJ relay provides an alternative by offering a PCB-mount solution. This allows designers to integrate the switching function directly onto the control board, which can reduce assembly complexity and enable faster production.
The smaller footprint also supports system miniaturisation. OMRON states that the relay allows designers to replace bulkier contactors while maintaining the electrical characteristics needed for high-voltage switching.
Growth of high-voltage DC applications
Demand for components capable of switching high-voltage DC is increasing as energy and transport systems move toward higher operating voltages. Grid-scale energy storage systems frequently operate in the 600V to 1000V range to support grid stability and the integration of renewable power sources.
Electric vehicles are also adopting higher battery voltages. Some vehicle architectures already operate at 1000V and above, with development underway toward 1500V systems that support faster charging, lower current levels, and improved drivetrain performance.
These developments place new requirements on power electronics and switching components. Devices used in pre-charge circuits must withstand high voltages while remaining compact enough for integration into increasingly dense electronic assemblies.
Product specifications and performance
The OMRON G9KJ is a type 1A relay with a single-pole, single-throw normally open configuration. Its compact dimensions measure 37.2 mm by 25.5 mm by 17 mm, supporting use in space-constrained electronic systems.
The relay is rated for DC link voltages up to 1500V. It offers a maximum contact resistance of 100 mΩ and a coil power consumption of 530 mW, characteristics that support energy-conscious electronic designs.
By combining high-voltage capability with a board-mount form factor, the device is intended to give designers an option tailored to pre-charge switching rather than relying on general-purpose high-voltage components.
Contribution to system reliability
Pre-charge relays have a direct effect on the reliability of power conversion systems. If the charging process is not controlled properly, high inrush currents can shorten the lifespan of capacitors, contactors, and protection devices.
A properly specified relay allows the initial charging process to occur in a controlled manner. This reduces the likelihood of nuisance trips or unexpected system resets and supports stable operation of the power stage over time.
OMRON states that the G9KJ was developed with this application in mind, enabling engineers to specify a component aligned with the electrical characteristics of modern high-voltage systems.
Availability
The G9KJ relay is now in production and available for integration into energy storage and electric vehicle charging designs.
About OMRON Electronic Components Europe
OMRON Electronic Components Europe is the European subsidiary of OMRON Corporation’s Device and Module Solutions division. The division, formerly known as the Electromechanical Components business, was renamed in 2022 as part of the company’s long-term strategic vision “Shaping the Future 2030.”
The organisation focuses on supplying component and module solutions that support advances in areas such as energy systems, communications, and industrial electronics. OMRON Electronic Components Europe operates through regional offices and a network of distributors across Western and Eastern Europe.
About OMRON Corporation
OMRON Corporation is an automation company whose technology base is described as “Sensing and Control + Think.” Established in 1933, the company employs approximately 30,000 people worldwide and provides products and services in about 120 countries and regions.
Its business activities span industrial automation, electronic components, social infrastructure systems, healthcare technologies, and environmental solutions.
