The main reasons that the North won the American Civil War were because they had a lot more men to fight than the South, they had factorites that made better weapons, (The south did not have factories like these), and more will power. Plus they had a good leader, Abraham Lincoln who had a lot of support from the border states.
A combination of greater population to draw manpower from, combined with even more industrial capacity to produce war materials, and the ability to blockade the southern ports to take away imports of all kinds.
The southern forces weren't ever able to overcome their lack of supplies and materials, such as a cannon and gunpowder. Bravery alone can't carry the day.
The north won the civil war because they had numerical superiority, excellent rail road links, etc., and an industrialized economy. They also won the war because of these reasons, and these reasons are the north's advantage in population and resources, the ratio of manpower between the north and the south, rail road links, monopoly in shiping and naval blockades, the failure in the King Cotton diplomacy, and the re-election of Abraham Lincolin to be president for the U.S.
The North won the Civil War because they were on the right side of human ethical issues. The South were hard core believers in slavery while the North did not. They also had more soldiers than the South which also contributed to their victory. The North also had more resources than the South and more military equipment. It was a combination of these factors that helped lead to their victory in the Civil War.