"Transformer overheating problem" Topic

Using a typical 12volt transformer, like the type used for external drives, lights, general house hold items, to head a print head.

Problem. Works well for a while, then over heated. May have killed it, have not tried it again.

Anyone know of a better transformer, or some gubbinz to go between the print head and transformer to stop it overheating?

I think the transformer is just too light weight.

Any ideas?

I think you picked it when you said 'better transformer'. Most cheaper transformers are only designed for intermittent or low power use – a 3D printer will run at full load for 8-16 hours for one print.

Basically look for an old fashioned 'brick' transformer that is rated to run continuously at twice the load you think it will run at as a minimum, one with a built in fan would be good.

The heavier the better – heavier usually means thicker wires, bigger heat sinks, fans and stuff. If its in a plastic case you might want to up the over power factor to 5-10.

Computer power supplies are a possibility, most have a 12 volt output as well as others, fans and are rated for continuous running – you just have to figure out which wires are the heavy duty 12 volt ones.

Thanks for that.

I had thought of a computer power supply or other larger transformer. I just used what I had at the time thinking it may work. Its good to hear from someone in the know. I think I have an old computer supply kicking around, but may look at getting something a bit more heavy duty.

Cheers.

All these "wall warts" and other consumer transformers are equipped with a thing which I forget the name of that melts at a certain temperature, breaking the internal connection. This way they can't start fires, which they would otherwise do. They should not reach this temperature under their normal operating load.

So once they stop working, they're done.

You definitely need to know the current demands of the device you're powering. Then get a transformer that will supply that much with a health margin. Twice as much is probably not necessary, but don't get a 250mA transformer for a 235mA load.

The bigger ones are more expensive, and this is simply and exactly because the have thicker wires, more plates in the core, blah, blah, more massive means better heat dissipation.

The real question is, what is the load of your device?

You could put something between transformer and load to shut things down if the current draw gets too high, but A) that will ruin your print at an unpredictable time and B) the transformer could melt before it trips. You could put something between the wall and the transformer to shut everything down before it melts, but that would still leave you with problem A. Easier than either of those is to just figure out what your current demands are and get a transformer that can supply that much easily.

Thanks, I'll take a look at the requirements.

Is a fuse, by the way.