The Next Generation of TDR Technology

Tag Archives: ‘Soft’ Fault

Pinpoint Wiring Faults with the SparkChaser

The SparkChaser is the star of our latest YouTube video. Three different testing channels are shown, which are used to detect & locate electrical faults:

Transcript:

I’d like to take a minute and introduce you to the SparkChaser, our revolutionary, new wire troubleshooting tool. This tool will allow you to locate opens and short circuits on live and dead systems in real-time. Now, let’s take a look at how this tool can be used to help you troubleshoot your wiring problems.

The SparkChaser has a large, easy-to-use touch screen interface. It also has a rechargeable lithium-ion battery pack, which will allow for normal use up to five hours. The SparkChaser has three different channels that you can use for testing. First, the intermittent channel, allows you to test both dead and live systems. The static channel allows you test dead systems for hard shorts and hard opens and the indirect channel allows you to use a clamp-on coupler to test both live and dead systems. We’ll go ahead and plug into the static channel for a test.

As you can see, we have the SparkChaser hooked up to a 40 foot open in a cable which has four different fault locations. I’ll go ahead and hit ‘Static Test’. Allright. Choose ‘Direct Demo’ from my list of wire types…and run a test. As you can see, the SparkChaser identified an open fault at 40 feet.

Allright, now let’s walk through troubleshooting an intermittent fault with a powered system hooked up. So, let me walk you through the system that we are going to testing quickly. And then we’ll hook the wires up so you can see how to connect through the intermittent channel to a powered system. We have a small power source here, representing about a 12V power source directly coupled into the 80 foot section of our cable here again. Now I’m going to go ahead and hook a load up to it which is this LED light that you can see off to the left-hand side of the screen. I’m simply hooking this up via alligator clips here. So now we’ve powered the LED light off of our supply. Let me just unhook this one side of our supply so you can see that – that is in fact what’s powering the light. Allright, now I’m going to go ahead and hook the intermittent channel of the SparkChaser up to our system. Okay, again this is directly coupled into the system. Now to run the test, all I have to do is go ahead and hit ‘Intermittent Test’. Again, I have to go in and I have to choose my cable type, right. For this, I’m going to go ahead and choose ‘Direct Demo’ again. I’ll go ahead and start the test. Okay, at the top of this screen, what you see is a waveform that represents the entire system here. I’m going to go ahead and start creating some intermittent faults on this system. As you can see, every time I create a fault, it’s represented in the waveform on the top of the screen.

I’m going to go in and I’m going to show you the details screen around some of these faults. So here, I just hit the detail screen. Now this gives us a blown-up view of the actual waveforms. I’m going to go ahead and toggle the waveforms off, and I’m going to re-add them so you can see what I’m talking about. So I’m going to re-add a baseline. I’m going to re-add the Fault Condition, which you can see is a significant deviation from the baseline. And now, I’m going to also add in the difference waveform. This waveform is actually what LiveWire uses to calculate distance-to-fault. You can also toggle, as you can see, between the different faults that were created. I’ll go ahead and close out of this screen now and again, show you the most important thing about our technology…the simple and precise answer…a short circuit at 80 feet.

Now we’ll show you the indirect coupling method that we use in the SparkChaser. Much like the previous test where we were directly coupled into a powered circuit looking for intermittent faults, the indirect method allows us to do this without having to directly couple to the wire. As you can see, we still have power on the line as you can see the LED light is illuminated. We’ll connect using LiveWire’s revolutionary indirect coupler. I’m simply clamping around the wire that we want to test. As you can also see, we’re about eight feet down the wire. The reason this is important is with LiveWire’s indirect coupling technology you are not required to test from one end of the cable or the other. You can clamp anywhere you can gain easy access and use our directional coupler to shoot the end of the wire that you want to test. Now that we’re connected, we’ll go ahead and start an intermittent test. Much like in the previous demo, we have to select a wire. We’ve selected the ‘Indirect Demo’ wire. I will go ahead and start the test now. As you can see, we also have a waveform which represents the entire system under test. I’ll now induce several faults using our blade. As you can see, several short circuits are being created at 72 feet, which is our total length of 80 feet minus the 8 feet of cable that is leading down to the power circuit.

Now that we’ve finished our testing, we allow you to save your data for later retrieval or to compare with other tests that you may perform in the future or you have performed in the past. To do this, we simply have to hit ‘Save Wire Scan Data’…it pulls up a very familiar Windows dialogue box…you can choose a directory from here, or you can plug in an external USB device so you can save the data off and load it onto other systems or other computers. So now, I simply have to hit ‘Save’ and the data is saved into the directory I chose. Thank you for spending a few minutes with us today, learning about the SparkChaser and how it can be used in your business to improve safety and reliability.

To order, go online to http://livewireinnovation.com/. If you wish to speak to a salesperson directly, call toll-free at 1-855-346-3358.

 

Non-Contact Connections for Reflectometry and Location of Faults in Cable Shields

The following slides were presented at the 2012 Aircraft Airworthiness & Sustainment Conference in Baltimore, Maryland on April 4, 2012. To view all slides, view the .PDF.
Non-Contact Connections for Reflectometry and Location of Faults in Cable Shields: Dr. Cynthia Furse, Dr. Brian Jones, Lucas Thomson

 

Time delay between Incident and Reflected Pulses tells distance to fault. The challenge: MANY faults cannot be replicated on the ground. Tests can't interfere with aircraft signals and aircraft signals can't interfere with tests.

 

TDR: Time  -  FDR: Frequency  -  NDR: Noise  -  STDR: Spectral  -  SSTDR: Spread Spectrum

 

'Hard' Fault is an open/short or near open/short that produces a LARGE electrical change to the system and produces a LARGE reflection to reflectometry. A 'Soft' Fault is caused by small impedance changes (corrosion, water, aging materials, etc.) and it produces a SMALL (maybe undetectable) electrical change to the system and it produces a SMALL reflection ot reflectometry.

 

'Hard' Fault: Open/Short or Near Open/Short  -  'Soft' Fault: Small impedance changes (corrosion, water, aging materials, etc.)  -  'Intermittent' Fault: Any fault (large or small) that appears and then disappears with time; 'Dry Arc' (vibration/stress induced; 'Wet Arc' (Moisture induced); 'No Fault Found"

 

Miswire: 8%; Failure due to corrosion: 7%; Short due to corrosion: 1%; Unspecified Failure: 6%; Short circuit unspecified cause (includes arcing incidents): 3%; Loose connection: 2%; Insulation failure: 3%; Chafed wire insulation leading to short circuit and/or arcing: 32%; Connector Failure: 9%; Broken Wires: 10%; and Other: 18%

 

Simulated Wire: TDR Signal & Partial wire fault location (high impedance short) with partial signal reflection due to a high impedance short circuit.

 

Live testing can locate up to 72% of wiring failures. Broken wires: 10%; Connector failure: 9%;  Miswire: 8%; Failure due to corrosion: 7%; Short due to corrosion: 1%; Unspecified failure: 6%; Short circuite unspecified cause (includes arcing incidents): 3%; Loose connection: 2%; Insulation failure: 3%; Chafed wire insulation leading to short circuit and/or arcing: 32%; and Other: 18%

 

During this 1 minute test, LiveWire SSTDR arc fault technology detected and reported the fault location more than 15 times prior to AFCB trip.