Unlike ordinary magnets, electromagnets heat up. These man made devices do everything a magnet can do and much more. They are particularly useful because it is possible to make them have any desired field strength and become stronger or weaker or even turned off.
Basically, electromagnets are coils of wire wrapped around a metal core, which in turn are connected to a battery. Although they are easy to make, they can have a problem with overheating if given more voltage than their wires can withstand. Fortunately, with careful design, this problem can be avoided.
As mentioned, it is possible to avoid heating of electromagnets. To do this, you can multiply the diameter of the electromagnets, i.e. the distance from one side of the coil to the other, by 3.14. Then, multiply this figure by the number of turns on the coil you are using.
This will give you the length of cable your electromagnet will use. If you measured the diameter in inches, the length will then be in inches. If the measurement was in centimeters, the length will be in centimeters.
Then, dwell the wire gauge resistance chart and select a random wire gauge. Look at how many ohms of resistance the wire gauge has per foot, meter, or your chosen unit of measure. Multiply this by the length of cable your electromagnet will require. The resulting figure will be the number of ohms of resistance your wire will have in that meter.
Next, divide the voltage of the battery you intend to use by the resistance of the cable you are considering. The result will be the current that will flow in that cable when it is connected.
You can compare this figure to the maximum current rating for that caliber wire on the current rating wire gauge chart. If the current your electromagnet will draw is greater than the maximum for which the meter is rated, do the calculations again, but with a smaller gauge wire.
The lower the gauge, the wider the cable and the more current it can carry. Repeat this process until you find a meter that safely transmits the current your device will produce without overheating.
You have to keep in mind that:
Generally speaking, yes. Electromagnets are in many of the everyday objects that we hadn’t even noticed could have one inside. Among their most frequent uses, and in which their presence could not be replaced by any other element, are electric motors, which usually heats the electromagnet very frequently.
To clarify all your doubts about why electromagnets heat up, at IMA we help you choose the type of magnet that best suits your needs. If you have any doubt, ask us.