### Brake calculation

greenspun.com : LUSENET : Elevator Problem Discussion : One Thread

I wanted to know the calculation requiered for the braking application of the lift. Also the material required for the piston. At what state will the coil be not able to give the required force.

-- Rahul Singh (rsingh@bhratbijlee.com), January 08, 2002

I suppose, one would have to take the net forces together in the system.

Momentum must be used, P = MV, mass x velocity.

now, disregarding rope weight at any point in the shaft, ( we have perfect rope weight compensation ) a car of mass 1000kgs, travelling at 2ms will give us a Momentum value of 2000kgs/s, in an upwards direction.

Now, assuming the counterweight has a mass of 1500kgs, and is travelling downwards at 2ms, it's momentum value is 3000kgs/s

The Net momentum in this system is 1000kgs/s downwards.

That is the inertial force that the braking system must overcome. How quickly it overcomes that is the real quesiton. Is the elevator going to stop as quickly as possible, or is it allowed to coast to a stop.