# How to design a Solenoid.

1. Jul 15, 2014

Hello everyone,
I have a few projects in mind that call for various sized solenoids. I have been experimenting with various gauges of magnet wire, however, every time the battery is connected, it gets too hot to hold. with that being said, is there a way to calculate how many volts and amps a given gauge of wire can handle? I don't know if there are any other variables to consider, but any info will be much appreciated.

P.S I am not sure if something like this has been posted already or not. I searched for solenoids, but came up with nothing.

2. Jul 15, 2014

### UltrafastPED

Much of this information is tabulated; see http://wiki.xtronics.com/index.php/Wire-Gauge_Ampacity

The heating is due to the current and the resistance: power dissipated (as heat) = current^2 x resistance.
As the resistance is so many ohms per unit of length, you can calculate the heat generated per unit of length.

The voltage limit depends upon the insulation, and how well the insulation holds up depends upon the temperature. For the highest loads you should choose transformer wire, which is designed for this type of application.

Solenoid calculators are easy to build, so you can easily find them on the web. For example, see
http://www.calctool.org/CALC/phys/electromagnetism/solenoid

Coil design calculators are less common, but can also be found. See
http://www.daycounter.com/Calculators/Coil-Physical-Properties-Calculator.phtml

The actual application can also make a difference - limitations on size, materials, available cooling, etc. are all important.

3. Jul 19, 2014