What is the benefit of using an electromagnet in a generator

[Amanda H]

Mentor note: Post moved from Educators and Teaching section
Hi
I would appreciate some clarity regarding using electromagnets as generators? Why are they used instead of permanent magnets specifically given that electrical power is needed? What is the difference between the power in and power out?

Thanks

 

[cnh1995]

Mentor note: Post moved from Educators and Teaching section
Hi
I would appreciate some clarity regarding using electromagnets as generators? Why are they used instead of permanent magnets specifically given that electrical power is needed? What is the difference between the power in and power out?

Thanks

Using electromagnets in the field, it is possible to regulate the terminal voltage of the generator as per the load. We can change the field excitation to regulate the voltage.

Look up Automatic Voltage Regulator (AVR) in power system.
https://www.google.co.in/url?sa=t&source=web&rct=j&url=https://en.wikipedia.org/wiki/Voltage_regulator#Automatic_voltage_regulator&ved=0ahUKEwjy3s-lu_nRAhUaTI8KHWHtA78QygQIKzAB&usg=AFQjCNFxzUhTp5qI35OHMtxkvngBMB74XQ

What is the difference between the power in and power out?

Could you elaborate this part?

 

[NascentOxygen]

I would appreciate some clarity regarding using electromagnets as generators? Why are they used instead of permanent magnets specifically given that electrical power is needed?

Electromagnets have historically been a feature of generators because their field was stronger than that of the permanent magnets available. Only in recent decades have permanent magnets become available with fields stronger than that of electromagnets, so you do find these being incorporated into motors, especially.

cnh1995's point about controlling electromagnets to achieve regulation is a good one, and possibly the advantages of both technologies could be exploited by designing a generator that employs a combination of permanent and controllable electromagnets.