# Delay of free fall with electromagnets

When you have a metallic ball hanging from a electromagnet and you disconnect the electromagnet, there is a delay between the moment you unplug the machine, and the ball starts falling. Why does this happen?

Are you sure there is a delay, or does it just appear to hang there briefly?
If there really is a delay I would think it has something to do with some brief residual magnetism somehow stored within the material of the electromagnet, but it is quickly lost.

Are you sure there is a delay, or does it just appear to hang there briefly?
If there really is a delay I would think it has something to do with some brief residual magnetism somehow stored within the material of the electromagnet, but it is quickly lost.
There is a delay because, when I change the voltage, the time that I measure changes as well. I need to add a correction into my calculations so that I can get a better result, but I don't know how.

I can't really offer any more than my first idea, that somehow the material of the electromagnet, a lot of which will be iron, temporarily retains some magnetism as if it were a permanent magnet.
Purely a guess, I'm sure somebody will be able to state categorically what is happening.
I'd be interested to know about it too.

berkeman
Mentor
When you have a metallic ball hanging from a electromagnet and you disconnect the electromagnet, there is a delay between the moment you unplug the machine, and the ball starts falling. Why does this happen?

What is the switch circuit like? Does it have a snubber circuit to keep the switch-opening arc to a minimum? What is the inductance of the electromagnet? Can you post the snubber circuit and any other components that are part of the circuit?

Do you have access to an oscilloscope? If so, and if there is a snubber circuit on the switch, you can measure the time constant of the collapsing field...

gleem