Electromagnet Questions

"Hello all of you Electric Engineers: Will you tell me if electromagnets are able to operate, by having a different voltage setting administered to them?"

Howstuffworks "How Electromagnets Work"

Electromagnet - Wikipedia, the free encyclopedia

Magnets and Electromagnets

Copper - electromagnets. Introduction.

The attrative power of an electromagnet is determined by the ampere-turns, i.e. the more turns or the more current the greater the attractive force.

Thus... for a given electro-magnet, if you double the voltage across it, you double the current through it, and you increase the attractive force. I won't say "double" because I don't have the equation handy.

Of course if your electro-magnet uses 30 gauge wire, and you try to put 20 amps of current through it, your attractive force goes to zero, and I would recommend having a fire extinguisher handy.

Also DO NOT try this with your wife. I tried this and her attractive force went way way down... in fact she was down right pissed.

Sincerely

Bill

Don't forget that for a given number of Ampere-turns, the attractive force also depends on the size, shape, and material of the core (especially if it is AC current), and the gap and surface area of the contact region between the electromagnet and the object being attracted.

And of course the magnetic properties of the object being attracted.

Dick

Most 12 volt electromagnets will fail from over heat if 24 volts is applied. The wire size, current, voltage and heat are all pretty well worked out with a least cost function to assure the most magnetic pull for the dollar.

You can cheat by raising the voltage and chopping the current and monitoring the heat build up and setting the on time so he magnet stays cool enough.

This is used on stepper motors to increase torque and can bet quite complex.

Nothing about ah I described is linear due to the inductance of the coil. But over small ranges a straight line works OK.

Gordon

Up to a point doubling the current will double the attractive force. The limits are

1. Saturation of the iron core.

2. Failure of the wire/insulation due to heat build up.

That's right dk....ya gotta think about those 5 time constants