Omron’s Sealed Power Relay Increases Voltage Rating for HVAC

Omron Electronic Components Europe’s new G6QE-1A4 relay expands the voltage rating of the company’s G6QE series of board-mounted (PCB) power relays to 480 VAC. The higher voltage rating makes the models ideal for commercial heating, cooling, and refrigerant applications, where prior variants of the G6QE series were limited to just 250 VAC.

Along with the increased voltage rating, the G6QE model can handle up to 36 A of AC load current and has a low coil-holding voltage designed to minimize power losses. 

G6QE-1A4 sealed relay for commercial HVAC. Image used courtesy of Omron Electronics

The sealed relay conforms with IEC/EN 60079-15 environmental protection standards for explosion-proof usage as required by systems such as commercial refrigerators and air conditioning compressors.   

Relay Features and Operation

The G6QE-1A4 is a simple four-pin, board-mountable (through-hole) electromechanical relay with a DC actuating coil and AC load switch. When the relay needs to be operated, a DC control current (up to 280 mA for the 5 V variant) passes through the coil, inducing a magnetic field that manipulates the switch and contacts.

Relay design and operation. Image used courtesy of Omron Electronics

When closed, the relay’s contacts can safely pass AC load currents up to 36 A at 480 VAC, with a closed path resistance of about 100 mΩ.  In the open state, the switch is rated to block voltages up to 2000 VAC, 50/60 Hz for 1 minute with 4500 VAC of isolation between the actuating coil and contacts.  

Depending on the requirements of the end application, G6QE model variants are available with coil voltages of 5, 12, and 24 VDC.  

Coil Holding Voltage Improves Efficiency 

An ideal switch consumes zero power, but in practice, some power is lost during operation. The G6QE series' power losses are minimized by a design that allows for a coil-holding voltage of only 35% of the rated voltage.  

The coil-holding voltage is the minimum voltage required when the relay is not being operated.  Before reducing the coil voltage to its holding voltage, the rated voltage must be applied for at least 100 ms.   

Coil holding voltage. Image used courtesy of Omron Electronics

The holding voltage allows close to 90% power loss reduction from the coil resistance compared to losses when operated at the rated voltage.  

Protection Features

Omron’s PCB-mounted relays offer varying levels of protection from environmental conditions. Encased devices protect the contacts from foreign materials but have limited protection against dust and dirt and no protection from corrosive gasses. Relays with flux protection prevent flux from entering the relays during the soldering process but also have limited protection from dust and dirt and no protection from corrosive gasses.  

Types of relay protection. Image used courtesy of Omron Electronics

Plastic-sealed relays offer the highest level of protection. They prevent the ingress of flux and solvent during the solder reflow and cleaning processes and shield the contacts from dust, dirt, and corrosive gases.  

The low-profile G6QE relay’s dimensions are 30.5 mm x 16 mm, with a height of 20.5 mm.  

DC Fast Charger Applications

In addition to commercial HVAC applications, the G6QE relay can be used as an AC safety shut-off in DC fast-charging applications or as a switching interface to relay power between the inverter and grid in energy storage systems.