As the HVAC industry switches to A2L and A3 refrigerants, which are generally considered more environmentally friendly, it is now dealing with refrigerants that are also more flammable.To meet this challenge head-on, Carlo Gavazzi has designed a “spark-free” three-phase voltage monitoring relay.Carlo Gavazzi's new three-phase voltage monitoring relays with spark-free technology. Image used courtesy of Carlo GavazziThree-Phase Voltage Monitoring RelaysCarlo Gavazzi's latest DPA relays are available as a single-pole double-throw or double-pole double-throw relay capable of switching three-phase 208-690 VAC and monitoring for phase loss and phase sequence. The DPA relays come in two mounting options: DIN rail and plug-in, and utilize screw terminals for both the line side and control side of the relay.The DPA relay is a mains-monitoring relay and is designed for use with A2L and A3 flammable refrigerants. The front of the device includes output and status LEDs for quick troubleshooting and will even indicate phase loss with motors running.If required, the DPA can be ordered with sealed components in accordance with IEC 60335-2-40 for the HVAC industry. While the DPA relay can switch loads without producing sparks, it must be installed in a temperature-controlled environment, as it is only IP20-rated and has an operating temperature range of -20°C to 60°C.Carlo Gavazzi has built its spark-free relays for HVAC systems using flammable refrigerants.Switching High-Voltage LoadsIf you look closely at a standard three-phase contactor, you might see a blue spark with every close-to-open transition. This spark is completely normal and, under normal conditions, does not cause any harm. If this contactor is installed in an environment where flammable gases are present, however, you run the risk of an explosion or a fire. For this reason, potentially-explosive environments rely on specially designed spark-free relays and contactors. Typically, these specialty devices include a certification.Carlo Gavazzi has designed its latest DPA relay to meet the modern demands of the HVAC industry and to help technicians troubleshoot main power without tools. The relays switch three-phase loads without producing a spark. Additionally, Carlo Gavazzi has included phase monitoring to indicate if a phase has dropped or is out of sequence with the other phases.
