Why do we give external source to an alternator? Why are we not using permanent magnet in place of an alternator? - Quora
![File:Meritan's permanent magnet lighthouse magneto alternator (Rankin Kennedy, Electrical Installations, Vol III, 1903).jpg - Wikimedia Commons File:Meritan's permanent magnet lighthouse magneto alternator (Rankin Kennedy, Electrical Installations, Vol III, 1903).jpg - Wikimedia Commons](https://upload.wikimedia.org/wikipedia/commons/4/43/Meritan%27s_permanent_magnet_lighthouse_magneto_alternator_%28Rankin_Kennedy%2C_Electrical_Installations%2C_Vol_III%2C_1903%29.jpg)
File:Meritan's permanent magnet lighthouse magneto alternator (Rankin Kennedy, Electrical Installations, Vol III, 1903).jpg - Wikimedia Commons
![File:Permanent magnet magneto alternator (Rankin Kennedy, Electrical Installations, Vol III, 1903).jpg - Wikimedia Commons File:Permanent magnet magneto alternator (Rankin Kennedy, Electrical Installations, Vol III, 1903).jpg - Wikimedia Commons](https://upload.wikimedia.org/wikipedia/commons/d/d8/Permanent_magnet_magneto_alternator_%28Rankin_Kennedy%2C_Electrical_Installations%2C_Vol_III%2C_1903%29.jpg)