How did you create the 3D Helix? Can you post a picture which shows the mesh? Without seeing what you have only general guidance can be given. I'll give it a shot, but if your basic geometry is not regular (ie., doesn't have good topology) to begin with, then this will not fix that issue.
"I want to split it from top to bottom (vertically) equally, to get multiple equal parts (segments). How can I achieve this, preferably without having to do a lot of manual work? (It's a big Helix). I need to get equal and small segments out of it."
You must already have some edges that define the shape of your helix. From your description it sounds like you want more horizontal edges evenly spaced between the existing horizontal edges. Some would call this getting better resolution across the vertical axis.
To do so,
1. If it is not already an editable poly, then convert it to an Editable Poly and enter the sub object edge mode
2. Select all of the Vertical edges (i.,e do not select any horizontal edges) that you want to divide with additional segments.
3. With all of these Vertical edges selected click on the little settings box next to "Connect" in the Edit Edges Rollout and select the the number of edges you want to add. Max will create them evenly spaced by default.
Hope this helps.
