Can I Use an Electromagnet to Repel Aluminum?

AI Thread Summary
An electromagnet created with a microwave oven transformer and a 1.5 D cell battery is attracting ferrous metals but failing to repel aluminum, which is paramagnetic and typically shows slight attraction to magnetic fields. The discussion highlights that aluminum and other non-ferrous metals do not generate eddy currents in a direct current (DC) magnetic field, which is necessary for repulsion. To create eddy currents and achieve repulsion, switching to an alternating current (AC) power source is recommended, along with using a step-down transformer to manage voltage safely. Adjustments to the model, including adding a resistor in series, can help prevent overload. Understanding these principles is crucial for effectively using electromagnets with non-ferrous materials.
Yummy Yum
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Homework Statement


I have made an electromagnet using the primary core of a microwave oven transformer and a 1.5 D cell battery.

I would like to use the electromagnet to repel an aluminum bar (1 in. dia., 3 in. in length, and 1/4 in. thick; it is shown in the picture)

For some reason, the electromagnet only attracts to ferrous metals, but does not repel non ferrous metals (like the aluminum bar). According to my research, some non ferrous metals will not be repelled by electromagnets, but aluminum should definitely be repelled.

I've attached a picture of my electromagnet

Homework Equations

The Attempt at a Solution


I've done everything I can think of to try and make the electromagnet repel the aluminum bar. I've tried switching the wires from positive to negative and vise versa, changing the battery size, and changing the thrust direction.

What can I do to make my electromagnet repel this aluminum bar?

Thanks
 

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Yummy Yum said:

Homework Statement


I have made an electromagnet using the primary core of a microwave oven transformer and a 1.5 D cell battery.

I would like to use the electromagnet to repel an aluminum bar (1 in. dia., 3 in. in length, and 1/4 in. thick; it is shown in the picture)

For some reason, the electromagnet only attracts to ferrous metals, but does not repel non ferrous metals (like the aluminum bar). According to my research, some non ferrous metals will not be repelled by electromagnets, but aluminum should definitely be repelled.

I've attached a picture of my electromagnet

Homework Equations

The Attempt at a Solution


I've done everything I can think of to try and make the electromagnet repel the aluminum bar. I've tried switching the wires from positive to negative and vise versa, changing the battery size, and changing the thrust direction.

What can I do to make my electromagnet repel this aluminum bar?

Thanks
Aluminum is paramagnetic, so it has a slight attraction to magnetic fields.
 
SammyS said:
Aluminum is paramagnetic, so it has a slight attraction to magnetic fields.
But, shouldn't non ferrous metals like aluminum and copper be repelled due to Eddy currents?
 
Yummy Yum said:
But, shouldn't non ferrous metals like aluminum and copper be repelled due to Eddy currents?
You don 't get eddy currents with a dc magnetic field.
As for when you thrust, that force is probably too weak and of too short duration to move the metal.
 
rude man said:
You don 't get eddy currents with a dc magnetic field.
As for when you thrust, that force is probably too weak and of too short duration to move the metal.
Sorry, I'm kind of new to this. So, if I wanted to create eddy currents, how would I adjust my model to use an ac power source?
 
For safety's sake I suggest a step-down transformer 115V to maybe 26V (a common type), then you need a resistor in series with your coil to keep the current manageable. Idea is not to overload the transformer.
 
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