At first, I had a particular goal, but I'm starting to doubt feasibility which has led me here.
Original Goal: Create a small (3in²) electromagnet with 100% duty cycle capable of holding at least 50lbs for 1-2 hours at a time.
I haven't fully killed this idea off, but I'm starting to think heat may be a significant issue here; so I'm considering a different approach.
New Question: Can I use a permanent magnet with holding force of +50lbs and use an electromagnet to disrupt the holding ability, which would then release it?
The idea here being that I could possibly use a magnet capable of holding hundreds of pounds, but it'd always be "on" so to speak. If my original electromagnet idea is plagued by heat problems; maybe I could leverage a powerful electromagnet at < 5s intervals to separate a metal object from a permanent magnet.
Does any of this make sense? Am I speaking jibberish? I'm not sure exactly which direction I can go, but my end goal is that I need to hold ~50lbs for 1-2 hours and then release it... with a magnet that won't become overwhelmingly hot.