Coil Winding Efficiency
Coil Winding Efficiency
(OP)
Given a spool with a specified ID, OD and length and knowing the diameter of the magnet wire, is there a formula that will state how many turns you can get on the spool? I would think it would vary quite a bit depending on the quality of the winding process (how "tight" it is).






RE: Coil Winding Efficiency
You are right in saying that the winding process determines the amount of wire that can fit. As long as the winder conforms to the "layer" winding technique, you can come quite close as follows;
Turns per layer = length/OD wire.
No of layers = radial hight/OD wire.
Total turns = Turns per layer * No layers.
Length Mean Turn = ((ID coil + OD coil)*Pi) / 2.
Length of wire = Total turns * Length Mean Turn.
Note:
1 Use the covered diameter for the wire.
2 Round answers down to iteger.
3 This is based on the assumption that the layers are aligned as follows;
O O O O
O O O O
The winder will usually wind as below which means that you could get a bit more on;
O O O O O
O O O O O O
RE: Coil Winding Efficiency
O O O O
O O O O
applies only.
RE: Coil Winding Efficiency
(The -1 is significant when there are few turns)
If layer insulation is used, the layer insulation will overlap and there is an additional factor besides the thickness of the layer insulation.
Quality of the winding process is important like BobM2 stated. Fill factors as low as 60% are sometimes recommended.
RE: Coil Winding Efficiency