# Calculating the requirements for magnetic levitation

• downtownjapan
In summary, the conversation discusses the use of an electromagnet to repel a permanent magnet and lift it up. The speaker is seeking advice on calculating the required magnetic field strength for the electromagnet to successfully repel the permanent magnet. They propose a formula and ask for feedback on its accuracy. They admit to having limited knowledge in science and physics, and welcome any suggestions from the forum. A link to a resource on calculating the force between two magnets is also provided.
downtownjapan
Hi everyone,

I am interested in using an electromagnet to repel a permanent magnet and lift it up, and I am thinking about how to go about calculating the required magnetic field strength of the electromagnet for this operation.
I have attached a rough conceptual drawing showing the electromagnet positioned underneath the permanent magnet, both enclosed in a tube to control the range of movement of the permanent magnet.
In the the section labelled Pic 1, the permanent magnet sits on top of the electromagnet, which is switched off. The permanent magnet is attracted to the ferrous core of the electromagnet.
In the section labelled Pic 2, the electromagnet is turned on. It repels the permanent magnet, lifting it up.

I am interested in calculating how strong the electromagnet needs to be in order to counter the attraction of the permanent magnet and repel it successfully.

Does anyone want to comment on the proposed following formula to calculate the required electromagnet field strength?

Required electromagnet field strength = permanent magnet's field strength + permanent magnet's weight

Am I on the right track with this reasoning?

Actually I studies very little science, and have never studied any physics at all. All of what little understanding I have comes from places like this forum - so any comments or suggestions would be much appreciated.

Thanks everyone!

#### Attachments

• magnetic repulsion.jpg
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## 1. How is the magnetic force calculated in magnetic levitation?

The magnetic force in magnetic levitation is calculated using the equation F = BIL, where B is the magnetic field strength, I is the current, and L is the length of the conductor.

## 2. What factors affect the requirements for magnetic levitation?

The requirements for magnetic levitation are affected by factors such as the strength of the magnets, the weight of the object being levitated, the distance between the magnets and the object, and the stability of the system.

## 3. How do you determine the minimum magnetic field strength needed for levitation?

The minimum magnetic field strength needed for levitation is determined by calculating the weight of the object being levitated and using the equation F = mg, where m is the mass of the object and g is the acceleration due to gravity. This force must be equal to or greater than the magnetic force calculated using F = BIL.

## 4. What is the role of the conductor in magnetic levitation?

The conductor plays a crucial role in magnetic levitation as it allows for the flow of current, which creates a magnetic field that interacts with the magnets to create the levitation effect. The length and material of the conductor also affect the strength of the magnetic force and the stability of the levitation.

## 5. Are there any safety considerations when calculating the requirements for magnetic levitation?

Yes, there are several safety considerations when calculating the requirements for magnetic levitation. These include ensuring that the magnets used are strong enough to support the weight of the object without causing any harm, and that the system is stable and can withstand any potential disruptions. It is also important to consider the potential risks of using high currents in the conductor and taking precautions to prevent accidents.

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