Prajna
Fixing things for the love of it
- Messages
- 529
- Location
- Castelo Branco, Portugal
The magnets never actually stick to the disc because their movement is restricted by the swash cylinder. We need a formula to calculate the inductive drag on the disc and a formula to calculate the push/pull forces.Think of it this way,
Completely ignore any forms of resistance, ignore the weight of the magnet, ignore stiction, ignore the weight of the metal, ignore the fact that the metal may not be 100% magnetic...
A magnet with a 1kg pull stuck onto a piece of metal will need a pull of 1kg to remove it.
You can test this easily with a magnet, a bit of metal and a spring balance.
It does not matter if you try to pull the magnet off the metal or pull the metal off the magnet. It will still need 1kg.
Try pulling the bit of metal off sideways (as if it was a rotating wheel) and it will still take 1kg
It may well take far less than 2kg to slide a piece of metal between 2x1kg magnets with opposing fields as the field interaction will be far lower.
If this action then causes the magnets to attract with full force you will get 2kg of force on the output side.
But, this 2kg of force is only generated from the 2kg of magnetic attraction to the metal plate so you'll need 2kg of force to get it out again.
So, if it only takes 100g of force to push the plate in you'll use 2.1kg of input to get 2kg of output.