OMRON Electronics has released the K8AB series of measuring and monitoring relays. The range includes seven models, which can monitor the integrity of both single and three-phase power signals. An eighth model, the K8AB-TH, will monitor temperature and is due for release in June 2005.
All K8AB units are DIN-rail mounted and use a 22mm-wide housing. The three single-phase models can be switched to detect either a too high or too low signal, and activate a 6A SPDT relay accordingly. Different models will sense voltage or current. In the case of the K8AB-VW, it uses a window comparator to detect both over and under voltage and drive one of two relays depending on the fault. Each of the three models can accept multiple input signals and is available with sources voltages of 24Vdc, 24Vac, 110Vac or 240Vac.
The three-phase units offer the same functions are their single-phase counterparts but can also detect phase sequence and phase loss (for both three and four-wire signals) as well as asymmetry.
The current detection relays can accept input ranges from either commercially available current transformers with signals of 0A-1A or 0A-5A, but the K8AB-AS3 has been tailored to accept input signals from Omron's K8AC-CT200L which has an output current range of 10A-100A or 20-200A.
Users are able to configure alarm detection levels and trip times. All units have led indicators for power indicator/operating status and trip warning.