Loose connection

[lquadros]

Hello everyone,

It is one common problem with our equipment that failure is caused due to loose connecton in wiring. This would at times, show strange symptoms etc. till the exact problem is located, a lot of downtime is in order.
Are there any modules or gadgets anyone knows, to locate this? Thanks in advance for your feedback.

 

[charlie b]

This is precisely the type of potential failure mechanism that thermographic inspections are designed to detect. Essentially, you take a photograph of the connections on a periodic basis. But it is not a "photo" in the sense of capturing light. Rather, you capture an image of heat. A loose connection will create a higher local temperature, and the "hot spot" will show up on an infrared image.

 

[DAWGS]

We work at industrial facilities that thermal image once a year, then schedual a shutdowm day and repair all equipment. Thermals will show all your hot spots witch may be loose connection, pinched insulation under lug, faulty breakers, bad sections of buss, corosion, ETC. Thermal imaging should play a major role in electrical maintenance were down time of equipment is important.

 

[LarryFine]

Here's an example of a thermal image. See if you can guess which contactor is about to fail:

From: http://images.google.com/imgres?img...channel=s&rls=org.mozilla:en-US:official&sa=N
​

 

[coulter]

Tell us, are these loose connections control conductors or power conductors?

The reason I ask is:
Trouble shooting loose power conductors is generally pretty easy. Thermal imaging is an excellent tool.

Trouble shooting loose, intermittent control conductors is often difficult. I've never seen thermal imaging used to find loose control conductors.

Another question - I know you didn't ask this, but I'm just curious: Is this high vibration equipment? If so, there are conductor termination techniques that mitigate high vibration loosening.

carl

 

[mdshunk]

Look into using a DLRO if you have one. Also, "tattle tale" fuses are good things to use for 24 through 240 volt analog control power troubleshooting.

 

[macmikeman]

I used to do time domain reflectometer testing on local area network wiring, and optical time domain testing on fiber optic jobs. Both were good for locating junk splices/punchdowns and other problems including flooded underground telco cables. I always wondered what a tdr test on a typical general purpose branch circuit would look like, and if that would be of any usefulness in troubleshooting loose connections at all. Anybody know?

 

[mdshunk]

I always wondered what a tdr test on a typical general purpose branch circuit would look like, and if that would be of any usefulness in troubleshooting loose connections at all. Anybody know?

I have a feeling that it would bounce right back like a boomerang even off a brand new snap switch. Hard to say for sure. Try it, and report back. :grin:

 

[macmikeman]

I can't, I sold off all that gear in 1990 but thats another story.

 

[lquadros]

trouble with bad connections

trouble with bad connections

Coulter,

The circuit I am refering to is a 24VDC circuit, 130mA, as measured with an Ammeter. Most of the circuits that we deal with would be of the same nature.

 

[ptonsparky]

I have a PLC setup in conjunction with solid state relays to find the first switch that opens. A Pico will work with more ladder logic involved. Not gadgets and I am not sure how they would handle a lot of vibration. On high speed fans we move the controls to a stable location.

 

[lquadros]

loose connection

loose connection

I am looking at, a process meter that can read mV drop accross a specific piece of circuit (a calibrated shunt) that is connected to a load. This meter can be scaled and also gives outputs that can be connected to PLC inputs. Open circuit and loose connection over and under currents can be located. But some wiring is involved.