About five years ago I performed a complete evaluation of every
connection at panels and transformers at the Fairbanks Memorial
Hospital in Fairbanks, Alaska using a handheld IR thermometer. It
worked very well. The temperature of terminals appeared directly
proportional to the amount of current they carried. I was following up
on a IR photo evaluation performed by a major electrical contractor
that found several hot spots but did not record the exact temperatures
or repair them. My job was to fix the hot spots . I verified the hot
spots, and in most cases found loose terminals. In one case I found an
overloaded 20 ampere circuit breaker. It was carrying 21 amperes
continuously and was running at higher than 75 degrees C. The
thermometer was a Raytek built by Fluke that cost about $200, as I
recall. Of course having a valid calibration by a lab before beginning
the job was important.
Yes, I have one. Bought it to balance the radiators in a new
central heating system, for which it is excellent. Next use
was to go round the house finding thermal leaks, i.e cold
spots inside or hot spots on the outside, and fix the thermal
insulation. Useful for checking the temperature of fridge,
freezer, oven, which it does instantly without waiting for
any settling time. You can measure your body temperature
(point it in your mouth, under your arm, etc). Pointing it
out through an open window will give you the outside ground
temperature. Pointing it up to a cloud gives you the air
temperature at cloud height (-50C is typical in winter,
even when well above freezing at ground level).
Actually, it's quite a nice toy all round. If you get bored
with the temperature sensing part, you can play with the
laser pointer, e.g. have the cat chasing the red dot around
the floor. I would imagine it could be quite educational
for children, but I would avoid one with a laser pointer
in this case.
There's just one thing they are completely useless for, and
that's measuring the temperature of bare copper, because it
behaves like a mirror in the infra-red. You may recall that
I originally bought it to measure flow and return radiator
temperatures in a new central heating system, i.e. bare
copper pipes;-) This is easily solved in this case by
painting the pipe, sticking a bit of tape on it, or pointing
the thermometer to the enamelled pipe stub on the radiator.
I also bought one for my dad who likes gadgets like this.
He has used it when cooking, e.g. to check that a cassorole
is reheated enough before serving (and found it wasn't the
first time he used it for this).
I have used the Sears $50 unit for checking operational battery
temperatures, works well for the price, none have failed in the field.
Today I bought a $6.99 unit on sale at Harbor Freight (requires
coupon that was emailed). About the size of an automobile keyless
fob, no laser spotter, and a wide angle. Need to hold it close to
the item, but essentially the same reading as a Sears unit for
room temperature objects.
Johnstone Supply has as a monthly special a $29 unit with laser,
but I have not tried one.
Photovoltaic Resources Int'l
Tempe Arizona USA
I use one for checking breaker and wiring temperatures, and it works well.
The advantages of the higher end units are adjustable emmisivity, and a
smaller target area at a given distance, meaning that you can get readings
while remaining further away from the surface (a definite advantage when
checking live panels). If you look at the specs on several, you will see the
differences in that figure.
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