Thermographic survey
- Thread starter kfenn
- Start date
- Status
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Thermographic survey
I have not. I recognize that thermography is a valuable diagnostic (even commissioning) tool, but I don?t think it is my place to ?require? it. The most I could do is to offer the suggestion, and see if the owner is willing to pay for it.
I have not. I recognize that thermography is a valuable diagnostic (even commissioning) tool, but I don?t think it is my place to ?require? it. The most I could do is to offer the suggestion, and see if the owner is willing to pay for it.
charlie
Senior Member
- Location
- Indianapolis
Re: Thermographic survey
Interesting, we have a two man crew that goes to all the substations in rotation as well as hitting all the bolted connections on our main lines. When they find hot spots, they will print them out and send it to our substation maintenance people or lines maintenance for repair.
I can't imagine doing their job day in and day out. It is a continuous cycle through the entire system. No, I don't know how long it takes to go all the way through.
Interesting, we have a two man crew that goes to all the substations in rotation as well as hitting all the bolted connections on our main lines. When they find hot spots, they will print them out and send it to our substation maintenance people or lines maintenance for repair.
I can't imagine doing their job day in and day out. It is a continuous cycle through the entire system. No, I don't know how long it takes to go all the way through.
iggy2
Senior Member
- Location
- NEw England
Re: Thermographic survey
I always call for a thermographic scan if there are shipping splits or bus connections field installed at MCCs, switchboards, etc.
There is always a lot of objection from the Contractor though, since 1) they didn't carry it like they were supposed to and 2) they have to inject rated current, and let things warm up before the scan. And, it always takes three times longer than anticipated, since they inject single phase current, one phase at a time.
Don't forget to require ampere measurements along with the thermal scan. One without the other is often not useful info. And the thermal scanner usually is not the one who will take the amp readings.
I always call for a thermographic scan if there are shipping splits or bus connections field installed at MCCs, switchboards, etc.
There is always a lot of objection from the Contractor though, since 1) they didn't carry it like they were supposed to and 2) they have to inject rated current, and let things warm up before the scan. And, it always takes three times longer than anticipated, since they inject single phase current, one phase at a time.
Don't forget to require ampere measurements along with the thermal scan. One without the other is often not useful info. And the thermal scanner usually is not the one who will take the amp readings.
charlie tuna
Senior Member
- Location
- Florida
Re: Thermographic survey
a infrared scanning without normal loaded conditions is somewhat useless. elevator disconnects are the number one problem found in most high rise buildings. bus ducts and associated taps should be scanned at least every two years--but under normal operating load. if the thermographer see's a two degree rise on a bus duct joint and the bus is only 20 per cent loaded ---he should realize there may be a problem---but if the bus is 80 per cent loaded this would be a normal rise in temperature. this is the importance of using qualified thermographs. i've seen them overlook major problems and at the same time cause the customer unnecessary repair costs.
on elevators--my opinion--all disconnects should be heavy duty and if the disconnect's amperage rating is close to the load of the equipment, the disconnect should be oversized....
a infrared scanning without normal loaded conditions is somewhat useless. elevator disconnects are the number one problem found in most high rise buildings. bus ducts and associated taps should be scanned at least every two years--but under normal operating load. if the thermographer see's a two degree rise on a bus duct joint and the bus is only 20 per cent loaded ---he should realize there may be a problem---but if the bus is 80 per cent loaded this would be a normal rise in temperature. this is the importance of using qualified thermographs. i've seen them overlook major problems and at the same time cause the customer unnecessary repair costs.
on elevators--my opinion--all disconnects should be heavy duty and if the disconnect's amperage rating is close to the load of the equipment, the disconnect should be oversized....
Re: Thermographic survey
On an on going basis it is nice to have an accessory for your digital meter that measures temperature. I have a Fluke 26 with a 80PK-IR Infrared Temperature Probe that is ideal for applications where object being measured cannot be touched and a 80T-150U Universal Temperature Probe that must be used by surface contact (24v or less).
It may not be a substitute for a general audit of a distribution system but they are one big help when troubleshooting.
On an on going basis it is nice to have an accessory for your digital meter that measures temperature. I have a Fluke 26 with a 80PK-IR Infrared Temperature Probe that is ideal for applications where object being measured cannot be touched and a 80T-150U Universal Temperature Probe that must be used by surface contact (24v or less).
It may not be a substitute for a general audit of a distribution system but they are one big help when troubleshooting.
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