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Last Post 05/07/2013 11:21 AM by  Will Lowes
CT Recommendation
 1 Replies
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Joe Rocci
New Member
New Member

05/06/2013 11:22 AM
    I have an application that requires current monitoring of a 220VAC load up 100 amps. I'd like to use a split-core CT. The output of the CT would drive a load resistor to develop a voltage that is sampled by an A-D converter in order to make various measurements. I'm looking at the 604-1000T for this. Since this is a 3000 turn unit, can I assume that, with 100 amps in the load, the output current would be 0.033A? Can I also assume that, if I load it with 1000 ohms, the output voltage would be 33V ? What is the insulation's voltage withstanding of this unit?

    Will Lowes
    CRM Staff
    New Member
    New Member

    05/07/2013 11:21 AM
    Dear Sir,

    Thank you for your interest in our product lines. The 604-1000T has 1000 turns so an input of 100AAC would yield an output of .1AAC. If you are looking for a split core CT with 3000 turns we have the CR3111-3000 which will take up to 100 AAC and saturates at 19 V RMS. The insulation voltage is 3500VAC/min.

    I noticed you mentioned using a 1000 ohm burden resistor. Typically we would use a much smaller resistor since the accuracy of the CT improves as you decrease the burden resistor. Also, since most A to D converters take a 0-10 VDC input, you will need to use a rectifier circuit to condition your signal. I have attached our application guide that details how this circuit is constructed.

    After you rectify your signal you can send it across a variable burden resistor to read to your converter. You will want to calibrate our CT using the variable burden.

    I also wanted to mention that CR Magnetics offers packages that have the precision rectifier circuit built in, and are calibrated to your input you need. Our CR4111S-100 True RMS Current Transducer will take up to 100AAC and output 0-10VDC. This unit is best for VFD drives and chopped waveforms. Our CR4211S-100 will read the average RMS Current and output 0-10VDC. This is a self-powered unit. Please see the attached catalog pages.
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