NK Technologies introduces the newly re-designed ASM Series Smart-Switch. These self-calibrating switches use the actual load current to set the trip point and provide the simplest way to ensure that a motor is working properly. These current sensing Smart-Switches are self-powered and self-calibrating to speed start-up and minimize installation costs. Three models are available to provide status monitoring, overload or underload, or operating window (overload and underload) functionality to suit particular pump, fan, heating element, conveyor or multi-load safety-interlocked application needs. The output contact is AC and DC compatible for use with any automation system.
“In many applications adjusting the trip point of a current monitoring sensor can be frustrating. The control cabinet must be open while power is on so that the load being monitored is energized and the tight space makes getting a small screwdriver in the right position challenging. An ASM Self Calibrating SmartSwitch solves this problem by using the actual load current to set the trip point,” says Philip Gregory, President, NK Technologies. “With the ASM series the sensor automatically locks onto the normal current level and self-learns and establishes a limit-alarm trip point to help users take corrective action before a failure occurs. Eliminating the need to manually adjust sensor trip points also improves safety and helps with NFPA 70E compliance by keeping screwdrivers out of an energized control panel.”
The ASM sensor slides or snaps over one conductor feeding the load. The contact controls the input voltage, AC or DC, to 135 volts to a controller or small relay. It takes just a couple of seconds of steady running conditions before the sensor locks onto the normal current level. If the load draws more current than normal or the current drops significantly, the sensor output will open. If the current falls below 85% of normal or increases above 125% of normal the contact will open, with no manually setting trip points and no adjustments needed unless a motor is replaced. Should a motor be replaced calibration is very easy, and within a matter of minutes the system is back in operation.
Test and evaluation units are available to OEMs at no cost. Visit the Engineering Resources section of NK Technologies website for access to numerous application notes, and a technology white paper on current sensing technology.