Electric motors are found extensively in both the manufacturing and processing industries. Both AC and DC powered motors are used to drive pumps, fans, conveyors and a broad range of specialized equipment. There are many types of motors designed for many different applications, however all require electrical current in order to generate the magnetic fields that are necessary to create rotation. By measuring this current useful information can be made available regarding the status of the motor and the equipment that is connected to it. This may be as basic as independently verifying the run status of the motor or in conjunction with a PLC, for example, to protect a pump against dry run. Thus current may be used to both monitor and protect motors and motor-driven equipment.
When conveyors jam and the drive motor continues to run, expensive mechanical damage to the drive components often occurs. By installing an NK Technologies’ Current Operated Switch an overload condition, detected by higher than normal running amps, can be used to switch off power to the motor before mechanical damage results. The switch setting can be adjusted so it is not affected by normal changes in conveyor load. Current operated switches are the modern day equivalent of less reliable electromechanical jam relays that have been in use for many decades.
In situations where there may be large variations in load an NK Technologies Current Transducer can be used to monitor conveyor motor amp draw and output this data to the conveyor control systems, commonly a PLC. The PLC may be programmed to accomodate different setpoints for different mechanical loads so that jam protection is provided from light to heavy loads. In situations where the conveyor is not able to accept analog signals NK Technologies has developed a patented transducer with a frequency output suitable for the Digital Inputs of most PLC’s.