Is it true that increasing winding count doesn't increase electromagnet force?

[dusan]

The formula for the pull force of electromagnet is:

Code: [Select]

F = (N x I)^2 x μ0 x A^2 / (2 x g^2)
N=number of windings
I=current
A=area
g=distance to metal

However if I increase number of windings, the resistance will increase linearly so the current will proportionally drop (if I keep voltage the same, e.g. battery). So if I increase the number of winding using the same wire it will not increase the pull force. Correct?

[radiolistener]

Yes, increase winding count leads to more longer wire which increase it's resistance, but you can increase voltage in order to keep current the same and get higher magnetic field strength

Also note that magnetic filed strength depends on current I (Amperage) and winding density (N loops count per L distance):

\$H = \frac{NI}{L}\$


So, there are two way to increase magnetic field strength - increase current or/and increase winding density. You can increase winding density by increasing loops count with keeping the same coil length or by reduce coil length with keeping the same loops count.

Both ways has some limit because wire has some diameter and you're needs to decrease wire diameter in order to bypass size limit which is also leads to increase wire resistance.

[donlisms]

And remember - there are constant current supplies as well as constant voltage supplies. 

[BeBuLamar]

Increasing number of windings would likely to increase magnetic force strength because the added resistance usually not very much if you use decent wire size.