Power Generation Magnets

Thread Starter


Joined Nov 13, 2010
Today I recieved a gift of a framed poster, where a rotor was being lowered into a stator at Hoover Dam during the period - 1939.

It occurred to me, how exactly do you handle and manufacture magnets that size?


Joined Feb 5, 2010
I believe they are only magnetic when current flows through the copper wire which is coiled around them.

Such large generators as the ones you mention will always use electromagnets and not permanent magnets.


Joined Oct 9, 2011
Kudos Kermit. You're quite right about that.

Large generators use field coils in place of permanent magnets. After the generator is running, a portion of the electric current that it generates is fed back into the field coils to maintain the magnetic field required to continue generating electricity. By varying how much current is fed into the field coils, a generator's output voltage can be regulated fairly accurately. Once a generator is stopped and electricity is no longer produced, the field coils have to be 'excited' VIA a external source or a battery in order to start the electric generation process again.

Here is a fairly well written beginners article on the subject. http://www.generatorguide.net/howgeneratorworks.html