Lifts Potential Energy Utilization

I would imagine this technology has always been employed...
In the form of a simple counter weight , or two lifts moving in syn'c.

Del

One could install a generator with an overrunning clutch to tap the potential energy of a lift returning to a lower level due to gravity and store the energy in a bank of batteries.

Of course, each system would require some engineering work to insure that the generator load matches the lift weight and speed to take advantage of the peak energy transfer without slowing the lift to the point that it begins to cause a loss of productivity.

its already being done.

Most variable speed drives (of the size needed to drive a lift system) brake by acting as an alternator and dump the recovered energy back into the power grid.

I've heard that old electric railways would have one engine going down a hill at the same time another was going up, that way the generated power from the first would help provide power for the second.

Of course it meant all the trains had to run exactly on time.

London Underground, among other metro rail system operators, employs regenerative braking.

regenerative braking.

Not to mention the old Victorian system of energy recovery in some underground stations with no moving parts and 100% reliability...!

But how!

It's impossible!

Oh yes...the track runs up hill into the station, the line then slopes down allowing the train to coast away from a stop.
Damn reliable gravity....

Del

But does the regenerated power go back to the rail or is it disapated as heat like it is on a diesel electric train?

Travis

All of the lifts I am familiar with (Elevators to the Yanks) use a counter weight to keep the motor size needed to lift them and their loads to a reasonable size. Hence, no great store of potential energy. Sorry, good thought though.

For movements on teh vertical the problem is different. In order to avoid any load fall in case of motor or power supply failure the system is self locking. Thus the motor has to be used in both directions. This for mechanical drives. The cabin brakes are for a cable failure.

Hydraulic elevators can be used with a part of energy recovery using the down stroke to load an accumulator used for the up stroke for instance.