noticed that my temps were going over 50c.
How hot is too hot for a Transformer. This is a locally made 12 to 15 amp transformer.
I am using a safety bulb 100 watt. You guys call it a safety lamp.
Can this impact the temps ?. It hardly glows.
What are the limits for heat sink temp and transformer temps. I have probes monitoring both now. I am monitoring the temps of the EI core metal plates.
This was the end of a long 8 hour shift with the music playing most of the time.
Is it the lamp causing it. Or the fact that its a poorly made local transformer. Because there is no way I was pushing it hard. Only the TDA7294 stereo amp was hooked up.
Heating is the same with the P3A amps also.
How hot is too hot for a Transformer. This is a locally made 12 to 15 amp transformer.
I am using a safety bulb 100 watt. You guys call it a safety lamp.
Can this impact the temps ?. It hardly glows.
What are the limits for heat sink temp and transformer temps. I have probes monitoring both now. I am monitoring the temps of the EI core metal plates.
This was the end of a long 8 hour shift with the music playing most of the time.
Is it the lamp causing it. Or the fact that its a poorly made local transformer. Because there is no way I was pushing it hard. Only the TDA7294 stereo amp was hooked up.
Heating is the same with the P3A amps also.
Yes I am butter Mr butter fingers. And it has saved my bacon more than one time. Do you think this is causing the issue ?. I know it drops the voltage by about 5 volts. It never glows. Under normal use.
Either way I want to know what is the max temp for a transformer. Yes I did search and believe it or not I did not find this topic being addressed.
Either way I want to know what is the max temp for a transformer. Yes I did search and believe it or not I did not find this topic being addressed.
If the transformer becomes too hot, losses are too high in it. My rule of thumb is if I can keep my hand on it, it is OK.
Is it hot at idle also?
Is it hot at idle also?
No on idle it never gets hot. Just when pushed for 8-10 hours. Its funny how nobody has documented or spoken about this in all these years. The other question I had was should the plates that make up the transformer measure any voltage. On commercial units I find that they totally isolate the steel core. So when you measure the body you get nothing. But on locally made units where the core plates are not isolated you do get a voltage.
The core plates are also known as laminations. They should have thin insulating coating on them or maybe black oxide insulation. Something like that. The thin insulation to minimize core losses due to eddy currents. If you can measure resistance between two adjacent laminations/plates then that's not good.
OTOH, if you are poking a DVM probe through the insulation and measuring some voltage, is probably due stray EM coupling between the core and the windings. Maybe capacitive coupling.
Anyway, from your description of the transformer only getting hot after running at high power for several hours, that seems more suggestive of the transformer being undersized or under-designed for continuous full load use.
Regarding the maximum safe temperature for a transformer, it depends on the particular transformer design. There are classes of transformer insulation that are safe up to certain maximum temperatures.
https://wiki.testguy.net/t/transformer-insulation-classes/60
https://mcitransformer.com/insulationsystemratings/#:~:text=Previously, insulation rating was denoted,overload capability of a transformer.
OTOH, if you are poking a DVM probe through the insulation and measuring some voltage, is probably due stray EM coupling between the core and the windings. Maybe capacitive coupling.
Anyway, from your description of the transformer only getting hot after running at high power for several hours, that seems more suggestive of the transformer being undersized or under-designed for continuous full load use.
Regarding the maximum safe temperature for a transformer, it depends on the particular transformer design. There are classes of transformer insulation that are safe up to certain maximum temperatures.
https://wiki.testguy.net/t/transformer-insulation-classes/60
https://mcitransformer.com/insulationsystemratings/#:~:text=Previously, insulation rating was denoted,overload capability of a transformer.
