I was thinking:

1) Create potion which increase enchanting effectiveness and drink it
2) Enchant apparels which increase potion effectiveness and equip them
3) Repeat step 1 and 2 a lot of time
4) Enchant apparels which increase enchanting effectiveness and equip them
5) Enchant anything you want

If there is a cap for enchantment effects, how many time I need to repeat step 1 and 2 to get that maximum enchantment effect?

The answer would be no