Electromagnet overheating?


This is my first post here, so please tell me if I should clarify anything.

I'm having the problem that my electromagnet is getting very hot and I can't figure out why. I bought the Intertec ITS-MS-2015 from Conrad.

It's a 12V 2.5W electromagnet with a force of 20N.

It's force is really nice (see some experiments). But like I said it get's very hot.
Some data:

R: 70 ohm
U: 21 V
Calculated I (12/70): 0.1714285714 A / 171 A
Documented I (2.5/12): 0.2083333333 A / 208 mA
Measured I: 0.17 A (in 10A mode) en 155 mA (in 200mA mode)

I use a Voltcraft USPS-600 adjustable DC adapter, put on the 12v mode, to power it. It says it can deliver 600mA. I also measured that it's giving about 12V.

When I mean hot I mean you can't hold it in your hands anymore.

Any tips would be greatly appreciated.

Any chance of an english version of the data sheet?

Hi CrossRoads

Most interesting parts:

  • Enclosed design
  • completely encapsulated
  • fully encapsulated data for 100% duty
  • limit temperature: 130 ° C.

Coil data:

Relative duty cycle (percent)                   100    50    25    10
Maximum duty cycle (seconds)                    ?      -     -     -
Max Power (Watts) at 20 ° C coil temperature     2.5

I also asked the questions at All about circuits.

I'm afraid the conclusion is:
It's heatsinking, lowering the duty cycle (using PWM), adding a resistor, or just making sure the surrounding parts can handle the heat.

When I mean hot I mean you can't hold it in your hands anymore.

Yes that is fine. A coil can run quite hot without any damage.

You say:-

  • limit temperature: 130 ° C.

You won't be able to hold that will you.

I would do :-

just making sure the surrounding parts can handle the heat

late reply but usefull for others.

You are using an electro permanent magnet.

An EP magnet vs EM requires a pulse. To make the polarity internal or external(- or +).

Just send a + pulse or - pulse to switch between magnet on and off.

EP magnets aka holding or sucking magnets do have a down fall. They usually require a capacitor as the pulse is a higher voltage.
Also They are not the best vibration magnets aka like a pager actuator.