Technology news: August 2012
High-capacity DC relay is `world`s smallest and lightest`
Omron claims to have developed the world`s smallest and lightest high-capacity DC power relay in its class. The 140g relay is 50% smaller and lighter its previous comparable relays, thanks to new sealing technologies and magnetic control methods. The company is also preparing to release other advanced relays including a 150A main relay, and an air-break switch pre-charge relay.
The new G9EN relay is aimed in particular at applications such as electric vehicles and robotic arms where its low weight and compact dimensions (28 x 40 x 50mm) will be an advantage. There will be a variety of models for different applications, with rated and maximum switching currents up to 300A, and maximum switching voltages up to 400V.
DC power relays contain pressurised gas to restrict arc formation by cooling. Usually, a ceramic housing is used to seal in the pressurised gas, but in the new relays Omron has changed from a conventional box-shaped ceramic case to a combination of ceramic plating and a metal casing. This makes it possible to maintain or increase the volume of the air-tight space of the main contact circuit structure compared to existing similar products.
The layout, spacing, and shape of the switching circuit and the permanent magnet circuit have been designed to extinguish the arcs that occur during DC load interruption across narrow contact gaps. This allows high-speed arc interruption regardless of the direction of the current, resulting in a non-polarised main contact circuit that has previously been difficult to achieve with DC relays using magnetic blow-out to interrupt arcs.
Omron claims that these are the first relays in their class with non-polarised contact circuits (contact terminals), helping to make them smaller and simplifying wiring and mounting.
The non-polarised circuits allow the relays to be used in applications needing two-way current flows. It is also not necessary to consider the mounting direction or orientation of the relay, making wiring and mounting easier, and reducing the risk of incorrect wiring.