I have a design where a permanent magnet is placed on top of an electromagnet. When the electromagnet is powered off, the permanent magnet is attracted to the iron core of the electromagnet. When the electromagnet is powered on, it generates a magnetic field which repels the permanent magnet, pushing it away. Both objects are contained in a cylinder which controls the movement of the permanent magnet. My question is - how can I calculate the minimum magnetic field strength that the electromagnet needs to produce in order to repel the permanent magnet?
I can calculate the electromagnet's strength in Newtons using these online calculators - http://www.daycounter.com/Calculators/Magnets/Solenoid-Force-Calculator.phtml http://onlinecalculators.brainmeasures.com/Electric/SolenoidCoil.aspx
I also know the weight of the permanent magnet, and I know the permanent magnet's pull force.
Is the electromagnet's field strength force required to repel the permanent magnet equivalent to the permanent magnet's weight plus the permanent magnet's pull force?