Hi guys,
I have the following elctromagnet:
https://he.aliexpress.com/item/P20-15-Holding-Electric-Magnet-Lifting-2-5KG-Solenoid-Electromagnet-DC-6V-12V-24V/32443244508.html?spm=2114.13010608.0.0.1A5Ccm
I'm connecting it directly to a 9V battery (though he supports 12v). And he warms up pretty high, it is hot to touch, something like 60 degrees C+.
I understand that electro magnet is actually a short circuit, so probably it is the reason it happening.
Is it ok ? should I limit the current some how ? should I cool it with a fan ?
Your link didn't work, so I can't get the specs...
Are you using the correct voltage for THAT solenoid - it seems to be a range of parts.
Some solenoids are only rated for intermittent use , not continuous.
The pull-in current required for a soloenoid is generally much higher than the 'hold' current - you could reduce the supply voltage ( perhaps adding a series resistor?) once pulled in and hence reduce heating.
Solenoids aren't a short circuit - they have a (perhaps low) resistance - what does the spec say?
regards
Allan.
https://www.aliexpress.com/item/P20-15-2-5kg-Electric-Lifting-Magnet-Electromagnet-Solenoid-Lift-Holding-DC-6V-12V-24V/32656605538.html?spm=2114.01010208.3.30.EC8LQW&ws_ab_test=searchweb0_0,searchweb201602_1_10065_10068_10000009_10084_10083_10080_10082_10081_10110_10111_10112_10060_10113_10114_10062_10056_503_10055_10054_301_10059_10099_501_10078_10079_10000012_10103_10073_10102_10000015_10096_10052_10053_10107_10050_10106_10051,searchweb201603_3,afswitch_5,single_sort_2_default&btsid=12caf9fc-6225-432b-8bcf-c601474757c1
English page, for those that don't speak whatever language was linked in the OP (Hebrew?).
EDIT: Or maybe not, AliExpress seems to have put some stupid cookie in my browser that redirects me to the Hebrew page when I use that link, even though I was looking at the English page when I copied it. Stupid.
An electromagnet isn't quite a short circuit, but it is still just a coil of wire. The only load it presents to the source is the winding resistance, so any power put into the electromagnet becomes heat. According to the table on the page, the magnet takes 3W of power @12V. It will be less with a 9V battery, but still enough to heat it up.
2 options to cool it down are to mount the magnet on a metal structure (which will act like a heat sink), and use a fan to blow fresh air over it.
Well that link worked for me Electro magnet
Although it is in some font I don't recognise.
That page is for 12 different models so which one do you have.
I would not rely on the data however because it shows the coil takes less current at 24V than it takes at 12V which is clearly against ohms law, maybe the tow voltage columns have been swapped over.
Yes a simple coil like this will get hot. There is not much to worry about until it gets hotter than 100oC, even then you are a long way off melting the insulation on the coils, it is just it is a bit of a safety hazard if it is touched.
Sorry for the hebrew link.
Aliexpress is a little bit annoying with his cookies.
this is the link :
https://www.aliexpress.com/item/P20-15-Holding-Electric-Magnet-Lifting-2-5KG-Solenoid-Electromagnet-DC-6V-12V-24V/32443244508.html
The magnet is the one in the link, the 2.5KG, it rated 12V 0.26A
Anyway, Thanks for your answers