Current Indicating Device

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deanpavil Power-User Join Date: Apr 2011 Posts: 104 Good Answers: 5	Current Indicating Device 08/01/2013 7:52 AM
	Many years ago I was working in a factory that had many 120 VAC controlled solenoids for hydraulic driven machines. It was difficult to tell which valves were actually on so one of the engineers there installed a device in the terminal panel on each of the hot wires that went to the coils. The device had a red LED attached and when the coil was energized the LED would light. The device was about the diameter of a quarter (US), doughnut shaped and about 3/8" thick. The coil wire went through the hole in the center. If my memory is correct the device was acting as a current transformer, but I don't know if there was anything else incorporated in the device. I would like to do this setup again on another project but I don't recall any part number or manufacture info. Does anyone know what these may have been called or where to find them? Thanks __________________ deanpavil
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Doorman Guru Join Date: Apr 2009 Location: Yellowstone Valley, in Big Sky Country Posts: 7425 Good Answers: 295	#1 Re: Current Indicating Device 08/01/2013 9:21 AM
	I have used relays with an LED indicator built into the case, indicating the state of the relay; LED is illuminated when relay is energized. I guess you could simply use the indicator in the relay (all the ones I can remember have green LED) as described. __________________ Semper Ubi Sub Ubi
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lyn Guru Join Date: Oct 2008 Posts: 42355 Good Answers: 1693	#2 Re: Current Indicating Device 08/01/2013 9:34 AM
	Indicator Lights
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JRaef Guru Join Date: Sep 2006 Location: California, USA, where the Godless live next door to God. Posts: 4665 Good Answers: 804	#3 Re: Current Indicating Device 08/01/2013 10:17 AM
	They are called "Current Flashers" in the simplest form, because all they do it power up an LED when current flows. You can also get a version that has a relay contact that closes so that you can signal a control system. http://nktechnologies.com/current-indicators/ampflasher-current-indicator.html __________________ All I every really wanted to be, was... A LUMBERJACK!.
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deanpavil Power-User Join Date: Apr 2011 Posts: 104 Good Answers: 5	#4 In reply to #3 Re: Current Indicating Device 08/01/2013 2:43 PM
	THat was exactly what I was looking for. Thank you very much. __________________ deanpavil
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70AARCuda Guru Join Date: Jan 2008 Location: Tucson, AZ Posts: 1331 Good Answers: 30	#5 Re: Current Indicating Device 08/01/2013 3:57 PM
	The device the OP describes was an "induction coil" which stole a small amount of the 'coupled' AC-magnetic field to "light" the indicating lamp. Basically, just a parasitic transformer that only got power when AC was present, hence the AC-lamp only illuminated when AC was "on". __________________ ...and the Devil said: "...yes, but it's a DRY heat..!"
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old salt Guru Join Date: Feb 2007 Location: Stronger Than The Storm Posts: 2394 Good Answers: 203	#6 Re: Current Indicating Device 08/01/2013 11:20 PM
	Besides lights have you considered audio alarms. Simple installation would be a bell/horn/buzzer with a different tone wired in parallel with each solenoid. If the noise level is high or the indicator not in the line of sight this should be considered. Good Luck, Old Salt __________________ Any day on the green side of the grass is a GREAT DAY!, --- me +++++++++. I believe creativity is an inherent part of everyone. --- Kermit T. Frog
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Joe Sparky Power-User Join Date: Jun 2009 Location: New Zealand Posts: 403 Good Answers: 5	#7 Re: Current Indicating Device 08/05/2013 1:17 AM
	Hi Deanpavi, the device that you are talking about is a current transformer. Your engineer was quite smart because even though the control for the solenoid was switched on, this device would only give indication if the solenoid was actually drawing current. IE the device may be switched on but if the solenoid coil is open circuit the indicator would not light up thus indicating a fault, smart move. Cheers Joe
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70AARCuda (1); deanpavil (1); Doorman (1); Joe Sparky (1); JRaef (1); lyn (1); old salt (1)

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