Hot Transformer
Phil Allison wrote:
"Fred McKenzie"
I have a couple of 20 Amp linear DC power supplies with hot transformers.
With no load, one gets up to 115 Degrees F after several hours. The
other gets up to 125 Degrees F. Measurements were made with an IR
thermometer looking at the top of the transformer.
** FYI there is a much simpler, low tech way to find the internal temp of a
transformer.
1. Measure the primary winding's resistance when at room temp.
2. Make the same measurement ( quick as you can) when the tranny's running
temp has stabilised.
3. Calculate the increase as a decimal factor and multiply that by 254 to
get the temp rise in degrees C.
Eg.
Room temp = 4 ohms
Hot temp = 5 ohms
Increase factor = 0.25
0.25 x 254 = 63.5 degrees C
Add on the actual room temp to get final result.
If the number is over 100C there is cause for concern.
spiffy trick. thanks.
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