Tuesday, June 26, 2012

Efficient, long life relays address renewable energy systems

Omron Electronic Components Europe has re-engineered two relay families specifically to address the very specific low power and long term reliability characteristics required for grid-connected solar PV and wind turbine inverters, charge controllers, battery powered UPS back-up systems and similar applications.

Grid tied solar PV inverters use pairs of monostable grid protection relays whose operation is essential to ensure system and user safety. The key challenges in the design of these relays are that their power consumption has to be extremely low yet they need to operate very quickly when required under hot start conditions. Omron has re-engineered its G7L-PV DPST-NO and G8P SPST-NO range specifically to meet these requirements, with a fast operate time of typically 20ms, long life and a low power coil. Both devices address the applicable standards which are IEC62109-1, 2 (July 2011) and VDE0126-1.

The new Omron G7L-PV features a large contact gap of over 3mm to ensure working voltage and over-voltage standards compliance. Contact rating has been increased to 280VAC with a 30A, AC7a Inductive load. Other changes made to the G7L-PV include re-profiling of both the stationary and wiping contacts, slightly harder contact material, stronger coil spring, changing magnet wire from Class B (132 deg.C) to higher temperature tolerant F (150 deg.C) and spool material enhancement. The G7L-PV has a class leading low power consumption of 320mW. The device features a compact, PCB mounting package of 52.5mm L x 35.5mm W x 41mm H.

Omron has also added the G8P-1A4P-BG, a new member of the G8P relay family, optimised for durable hot start capability and with good coil and contact temperature rise characteristics. The newly re-engineered device has a contact gap of over 2mm, and a rated electrical life of 30k operations at 20A 250VAC. This relay is even smaller than the G7L-PV, and is supplied in a plastic sealed PCB mounting package of 32.1mm L x 27.2mm W x 20.1mm H.

To achieve a durable relay solution, Omron has submitted the new relay designs to meticulous testing and design enhancement, allowing them to be used with confidence in renewable energy systems around the world.

Omron is offering the relays with 12 and 24VDC coil voltages as standard, others are available on request. The devices are approved to UL, CSA and VDE standards – VDE approval is pending on the G7L-PV. Both feature a wide ambient temperature operation range -55 to +85 deg.C.

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