ECN Forum Forums General Topics of the Trade General Discussion Area Preventative Maintenance on 480v MCP

I work with Johnson Controls Inc. at Intercontinental Airport Houston Texas. We recently had an issue with a 3/O wire melting due to a loose lug. We have been discusing better ways to do preventative maintenance in our motor control panels. Is there a type of heat gun device that will let us know if there is a loose contact causing the wire to melt due to resistance or is tightening every lug and contact our best bet to ensure this does not happen in the future. I would greatly appreciate any input on this matter.


Bagroom Manager, Rob Perr.

I have seen thermal imaging "guns" that will sense the hot spots and will thus show you the high resistance connections.
Sorry I don't know who makes it.

Chris

Hi, Rob.
To add a little bit more to what Chris told you, our Fire Department recently purchased a thermal imaging camera from a company by the name of Bullard, located in Kentucky (sorry, I don't know the city). We use this for locating hot spots inside walls and ceilings (from fire, ballasts, or high resistance electric connections which are "cooking" in a hidden area). Works great, but the cost of this thing is horrendous...$9800.00! Hopefully, someone can put you onto something a little more reasonable.

Mike (mamills)

Found a URL for this company... http://thermalimager.bullard.com/whybullard/
(along with an address and phone numbers)

[This message has been edited by mamills (edited 02-14-2002).]

Thermal imagers or temperature indicators are nice but only give you a "snapshot" of what is going at that very instant. There are available some small stick on tabs that have a permanent change in color at a specific temperature. some are marketed for electrical use. You put the sticker on the termination and then every few months you just look for the color change and take any corrective action that may be required at that time. Take a look at this site: http://www.ydxlabel.com/ydxlabel.htm

I haven't tried them yet, but they look like a good idea.

Graingers, and lots of others, also sell non contact infra red thermometers. I've used them for a long time. They don't make a permanent record of the area, but they will let you know you have a hot spot, you can also run them up and down columns of breakers and check for loose connections or overloaded conditions like that. Used them for several major maintenance programs including Dulles Airport. They also go between $300.00 and $600.00 making them a bit more palatable.

I have a Fluke 65 Infrared Thermometer - believe it cost around $100 - works like a charm...sends out an infrared beam and you can get readings on warehouse conduit 25' up in the air...breakers, lugs, etc.

I've played with the infared themometers but don't have one.

The downside (and maybe they've come out with something better) is that it took nearly a second to get a temperature reading which meant scanning a row of breakers would have been terribly slow.

And the thermometer "sees" a circular area just like a camera lense does - so at 12", you're reading the temperature of whatever its pointing at but at 25', you're reading the average temperature of a circle maybe 2' in diameter.

The only problem with all of the scanners or non contact thermometers is that if the connection or device is not overheating at the time of your scan, you won't see the problem.
Don(resqcapt19)

You can get a reliable non contact gun-type temp. sensor for as little as $125.00 from Sunshine Instruments. Try www.measurebetter.com and contact Tom.

Maintguy - re: 2' beam pattern at 25' - the Fluke I have has a VERY tight beam - at 20' the light beam does not cover more than a 3/4" conduit....I use mine to check to hot conduit - checking for harmonics, poor connections.