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Seamlessly Convert a CT Signal to a Standard 4-20mA Output with New CTC Signal Converters from NK Technologies

NK Technologies 1/1/2015

CTC Signal ConvertersNK Technologies introduces CTC Series Signal Converters.  With the CTC series users can utilize an existing standard 5 amp secondary CT or low voltage (0.333 VAC) ProteCT™ current transformer with non-contact ranges as low as 0-5 amps over a conductor to produce a standard 4-20mA two-wire, loop-powered signal.  With DIN rail mounting and a 24 VDC loop-powered supply, the CTC series provides simple snap-in installation that requires no calibration because the primary current transformer ratio provides the scaling required without any installer intervention.

“The CTC makes life easier for users who need to monitor current in applications where it is impossible to install a one-piece sensor,” says Philip Gregory, President, NK Technologies.  “And because the sensor output is industry standard, two and one piece solutions can be mixed in the same controller cabinet.” In some applications, such as monitoring a high voltage system, using a two-piece solution consisting of a current transformer and separate signal converter works better than using a one-piece sensor.

"A two-piece solution is also a better choice when the system is supplied with bus bars, making installation of a standard NK Technologies one piece current sensor over the conductor extremely difficult or even impossible. “In a two-piece solution the secondary of a standard 5 amp current transformer is connected to the input terminals of the CTC device, the CTC secondary is connected to a nominal 24 volt DC supply and then to the PLC or panel meter input.  The converter then produces 4mA when there is no current through the primary CT, and 20 mA when the CT has full range current present,” explains Mr. Gregory.

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 technology white paper on current sensing technology.