Stators-Molded or Unmolded

Discussion in 'Electrical' started by mtmasean, Jul 20, 2011.

  1. mtmasean

    mtmasean Active Member

    104
    26
    0
    Not sure which one I have but, was wondering one, does it make a difference molded or unmolded stator other than the price? Two, how can I find out which one I have before I remove the stator? Leaning towards the molded one but, not sure if that will hold more heat? Any thoughts or recommendations?
     
  2. Hoople

    Hoople Account Removed

    7,198
    0
    34
    I am pretty sure almost all HD factory stators are not molded. I have never had a non HD molded stator in my hand to see how well it was molded or potted, but I can comment on the reason why you may want or not want a molded stator.

    It all begins with the wire used to build stators. The wire used is called magnet wire. Everyday rubber coated wire can't be used because the rubber insulation takes up too much valuable space when winding a coil, so instead of rubber coated wire,,1 or 2 coats of urethane is used to cover the copper wire and provide insulation. The thickness of this urethane coating is very thin in comparison to a rubber coated wire. The reason for this is because you can make more turns (more copper) in the given area you have to work with.

    When current passes through copper wire, the copper wire will vibrate due to the magnetic field that is generated. This "micro motion" of each turn of wire allows strands to rub against each other. In time this rubbing will cut through the urethane thus allowing an electrical short to take place from one copper turn to another copper turn. It takes just 1 shorted turn of wire to destroy the entire magnetic flux of the concentrator or pole.

    Potting or molding of the flux concentrator or poles, holds the wires in place when they vibrate thereby increasing the life of the stator. (or motor, or transformer etc)

    You do have to inspect the quality of the potting or molding that was done to see if was done correctly and if will actually help in increasing the life of the item. But generally, potted or molded coils of magnet wire will last longer because of reduced damage caused by "micro motion" of the copper turns. (A big positive for potting or molding)

    The downside of potting or molding is that heat is trapped within the wire instead of being dumped into it's surroundings. (A Big negative for molding or potting)

    In my opinion, the temperature rating of the urethane used (there are SEVERAL different qualities) and the method used to wind the coil (needle winder) is more important than whether it is molded or potted. I would rather have an unpotted coil using H temp rating urethane (heavy coat) wire than a potted coil using a A temp (single coat) rated wire.

    As you can see, the choices and questions are many. Unless you can get all the answers, it's best to just stick with a brand name and company reputation you can trust that made the product.
     
  3. mtmasean

    mtmasean Active Member

    104
    26
    0
    Thanks Hoople. I'll probably go with Accel since I know that brand. When I asked my local HD shop they didn't know if it was a molded or unmolded not to mention it isn't available any more through them. So it would have to be an aftermaket one. I would wait to order it (the same kind already installed)when I take everything apart but, I would rather have the part on hand so I can put everything back together and not have to wait a couple of days for the part to arrive. So I guess it will be 50/50 90 I'll guess the same type.