Posted 7 Nov 2014 I have project where I need to measure motor current but I do not need to control the speed of the motor since it would always be running at full speed. Do I still need to use VFD to get feedback or is there cheaper way to measure the current? Share this post Link to post Share on other sites
Posted 7 Nov 2014 Inline Amp meter that mounts to the front of the panel? 1 person likes this Share this post Link to post Share on other sites
Posted 7 Nov 2014 If you just want to measure the current in the PLC, and you already have thermal overloads, you can use a product like this: (http://www.redlion.net/sensors/current-sensors) Look in the "Current Transducers" area Another option is to use a Smart Overload Relay such as the E3 Plus (http://ab.rockwellautomation.com/Circuit-and-Load-Protection/LV-Motor-Protectors/E3-Plus-Overload-Relays). You can get the current feedback using communications (DeviceNet, although you can get Ethernet/IP with an adapter. Allen Bradley promises us that an ethernet model is coming out) Hope this helps. Share this post Link to post Share on other sites
Posted 7 Nov 2014 (edited) I must be getting old. I recall when measuring motor current was standard and the questions were; can I and how do I measure this if I have a VFD. Edited 7 Nov 2014 by RussB 1 person likes this Share this post Link to post Share on other sites
Posted 10 Nov 2014 I need to feed the measurement to PLC so the E3 Plus from Allen Bradley might be the best option. Another question would be how do I measure current for device powered by 12Vdc? Share this post Link to post Share on other sites
Posted 11 Nov 2014 I've never done this before, but after searching "DC Current Transducer" I found this: http://www.ce-transducer.com/Current_transducer.asp In particular on that page there is this: http://www.ce-transducer.com/CE-Az11-1.asp It just might fit the bill. Share this post Link to post Share on other sites
Posted 11 Nov 2014 (edited) These work reasonably well and aren't terribly expensive. http://www.automationdirect.com/adc/Search/Search?searchquery=CURRENT%20TRANSDUCERS&cmd=Search&fctype=adc.falcon.search.SearchFormCtrl&TxnNumber=-1 Edited 11 Nov 2014 by Mendon Systems Share this post Link to post Share on other sites