Lifts & Elevators

Because. That's what is required by the design engineer.

Is there any method or calculation basis?

to my calculation esp in Hydraulics where the power required is 2.5 to 3 hp the elevator industry is using 10 to 12hp what are the factors considered to reach the values.

I am not an elevator designer, so I can only speculate that this is done to satisfy performance and safety requirements.

Over specification is rarely tolerated in for-profit companies.

To accelerate the maximum rated load (plus an overload allowance for idiots).

Does it mean that an overload allowance had to be 4-5 times the design; where we consider 0.2 - 0.3 factor on load; 0.7+ for safety; and that too where the load is not direct for there is counter balance mechanism which reduces the active load to large extent.

"0.7 Fs"?

If it's people - Fs = 2.5 to 5.0

Besides, bar some small additional loss in a larger electric motor - it only draws the Watts the load requires.

The counter balance, usually, is near the mass of the car; meaning twice the 'visible' inertia to accelerate/decelerate.

Use that 1/2 M V² one, on a couple of tons through 4 m increments at say 0.25 g

But there is a guy on CR4 who blogs on lifts and escalators - why not ask him?

thank you for a good message.

You are very welcome - enjoy the forum.

The counter balance is usually equal to the cage plus half the maximum load.

Depends

OK, I've only dealt with industrial lifts of several tons payload at least.

One of the Ottis trainers favourite tricks on the lift rescue course was to get the lads to manually wind a 4 tonne lift in what they thought would be the easiest direction. It was funny watching them sweat!

Lifts and Elevators play important role in high class buildings and mall. We need to contact strong lift suppliers as essem engineers