# Spinning magnetic field through a coil-can this propel engines?

Spinning magnetic field through a coil-can this propel engines??

Magnetic field through a coil produces torque in the coil. Suppose we have a coil.The set up is such that the magnetic field passes through the coil.Now,if we spin the magnetic field along with the coil,the coil will keep spinning.an axle can be connected to the coil.and a much heavier object,say a ship propeller can be attached to the axle.as the field spins[this can be done by keeping a very powerful horseshoe magnet over the coil and spinning the magnet],the coil will spin,and the axle along with the propeller will spin. Is this possible??

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berkeman
Mentor

Magnetic field through a coil produces torque in the coil. Suppose we have a coil.The set up is such that the magnetic field passes through the coil.Now,if we spin the magnetic field along with the coil,the coil will keep spinning.an axle can be connected to the coil.and a much heavier object,say a ship propeller can be attached to the axle.as the field spins[this can be done by keeping a very powerful horseshoe magnet over the coil and spinning the magnet],the coil will spin,and the axle along with the propeller will spin. Is this possible??
It does not sound like a practical motor configuration.

Instead of spinning the magnet, why not just spin the propeller shaft directly?

This is because it will take a lot more energy to propel the shaft directly.The idea is to use very little energy to spin the magnet-the torque by the magnet will then spin much heavier objects.

berkeman
Mentor

This is because it will take a lot more energy to propel the shaft directly.The trick is to use very little energy to spin the magnet-the torque by the magnet will then spin much heavier objects.
False. Sounds like you are trying to come up with an over-unity engine, or similar. Discussions of such (impossible) devices are not allowed on the PF.

But sir,can you please tell me where exactly i am going wrong?

berkeman
Mentor

But sir,can you please tell me where exactly i am going wrong?
You are going wrong in thinking that you can get more energy out than you put in. The energy has to come from somewhere. There is no "magic" energy.