Occasionally a customer will call our Technical Support to ask if we offer any Normally Closed (N/C) current sensors. While it is true that all of our self-powered AC current sensors only offer a Normally Open (N/O) Solid State contact, we do carry several relay & AC sensor combinations that can be configured to function as powered N/C current sensors. Specifically, those models are the RIBXLCRA & RIBXLCRF, RIBXLCJA & RIBXLCJF, RIBXLSRA & RIBXLSRF, and RIBXLSJA & RIBXLSJF.
Each of the above models comes in a 4″ by 4″ plastic enclosure and contains either a solid core or split core remote current sensor. When wired as shown in Fig. 1, the device will function as a current sensor with a SPDT relay output.
How it Works:
When current through the load wire exceeds the threshold (see datasheet) of the device, the sensor feedback contact will close. This will allow the voltage connected to the upper screw terminal to reach the on-board relay coil. Once the relay coil is energized, the N/O relay contact will close and the N/C relay contact will open.
Fig. 1 most closely represents the RIBXLCRA & RIBXLCRF, but all other models would be wired similarly. The relay output of the RIBXLSRA & RIBXLSRF and RIBXLSJA & RIBXLSJF is slightly different, as it is only a SPST that is selectable between N/O and N/C, and those models also have an override switch built it.
If you have any questions about this blog or any of our products, please feel free to call or email our Technical Support, and we will be glad to help.