I have this project consisting of a current sensing relay controlling a motor control relay. The motor is a small 120 v AC motor with approx. 2 amp draw. The two devices that I need to sense a current draw on are both 120 v AC. Either one activated needs to energize the motor control relay. I used a rather simple and inexpensive current sensing relay, that has a contacts rating of 50 ma. which is adequate to control the motor relay. The current sensing relay is designed to have at least 4 amps of AC current flowing in the wire passing through the sensing portion of the device to close its contacts. It states in the instructions, if you need to activate the relay on a lower current, you can loop the wire a few turns through the sensing portion to achieve this. Of the two devices that I need to sense current draw on, one of them has a 70 ma. draw and the other has 1.3 amps draw. In order to sense these lower currents I had to loop the wire a few times and as a result the increased sensitivity is such that external 120 v AC line spikes can cause the motor relay to chatter. (false trigger) In my searching for an alternate current sensing relay with higher contacts rating and a time delay circuit built in, which could be used to minimize the spike issue, the best I have found so far has a trigger current range of 100 ma. to 1000 ma. and a contacts rating of 15 amps. I could use this device to control the motor but my 70 ma. draw device would not trigger it and these guys are kind of expensive.
I would appreciate any suggestions with a way to stop the false triggering. Thank you.
I would appreciate any suggestions with a way to stop the false triggering. Thank you.