Is there a problem if my copper coils for an electromagnet are heating up?

 I have built a few little nail style electromagnets and they all heat up.  If there is less power its slower but it still does.  I have experimented by using this heat but on smaller coils it will start to smoke because it is to hot.  This made me wonder if this is a short or actually an apply-able heat source.  On a very large coil heat is generated but not enough to make smoke so is guess that it is actually losing power so it can't be a short.


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NachoMahma7 years ago
.  If you are using DC, then your coil is a low-resistance load. Not exactly a short, but it can be close. You can measure the resistance of the coil and you should know the voltage, so Ohm's Law will tell you how much power will be dissipated. You only need 2-5 Watts for a mug warmer.
.  Mug warmers work exactly the same way, they just use "high-resistance" wire (or resistors) to generate the heat.
jj.inc (author) 6 years ago
 Wow!! I would like to thank everyone and also say, DON'T attach a 15v dc power source to a coil around a straw.  The straw will cut clean off and melt all over your floor and stink and smoke to. 
08techgrad6 years ago
If you're going to use your electromagnet for induction heating, you should look up how to build a circuit to monitor the temperature by cycling when to power on and off.  You might want to make some upgrades to the circuit in the meantime.
jj.inc (author) 7 years ago
 Thanks everyone I just wanted to make sure I wasn't going to do damage to anything or blow up batteries.  
Heh. I remember i tried that one time. I wrapped a big magnet with a lot of 26 gauge wire and plugged it into the wall. the whole thing caught fire and the magnet became a dud.
redrider4697 years ago
It's not a short but just to make this answer brief, this video will answer all of your questions.
rickharris7 years ago
Passing electricity through a resistance (the wire in this case) creates heat, How much depends on the resistance of the wire.

You can calculate the power used Here  if you know the resistance, voltage and current.

This is essentially how an electric fire works. As long as the temp remains reasonable - i.e. below the melting point of the insulation and or the wire you should be OK.
Just curious: Is "electric fire" the UK term for a US "space heater"?
Make sure the wire that you are using has a coating.  The wire naturally heats up, because the energy has to go somewhere.  So the energy is given of as heat.  I have made some electro-magnets before and they do get warm.  Also a friend of mine has an electro-magnet that gets really hot if you leave power applied.  Yes this could be used to heat a coffee mug.  But if you are going to do that you should look up some 'ibles that deal specifically with that, so you know that everything is hooked up right so that you don't fry the battery.