No offense taken i have never taken a microwave apart or have any experience with transformers so that is all very helpful everyone has been great on this forum you guys have given me lots of good info

 

Your original question needs some clarification...a stronger electromagnet to do what? Do you want to lift a heavy iron weight or a thin steel sheet? Orientation of an electromagnet's poles will give varying results; ie, shallow field, deep field, etc. Trying to lift a bundle of re-bars, for example can be difficult with a single flat face magnet...even multiple ones on a beam. A lot of electromagnet design is proprietary...not given out to the public in general because of commercial interests and markets. Some general rules will help you; The amperes x # turns product will determine the magnet's strength. A easily magnetized iron circuit of low carbon steel makes the best electromagnet. A very strong deep field electromagnet can be made by machining a steel cup with a center pole that will accept the coil bobbin. The outer ring of the cup is one pole and the center is the other pole. Many magnets are wound with aluminum strip to economize weight instead of wire, but the AT product remains the same. Watch your heat!
After a point, adding more turns does not increase the magnet's strength... this is called the saturation point...But it adds a lot more heat...You must do a balancing act with your designs! Another factor in lifting something is how close is the contact with the object you are trying to lift...trying to lift a painted object is difficult because you cannot get the magnet face closer than about 3 mils (primer & paint thickness). A well designed magnet will not lose much of its strength due to heating of the coils (saturation again).

Cheers, DPW [Everything has limitations...and I hate limitations.]