On 14/11/2015 10:29, Mark Goodge wrote:
On Sat, 14 Nov 2015 09:36:51 +0000, Clive D. W. Feather put finger to
keyboard and typed:

In message
-sept
ember.org, Recliner wrote:
I'm a little surprised that they claim it uses less power than a
conventional lift. If you have to raise a given mass through a
given vertical distance, shouldn't the answer be the same?

That assumes 100% efficiency in the mechanism. Not a safe assumption.

Yes, I agree about the *energy* consumption. But perhaps it gets away with
a less powerful motor, as it's slower than a normal lift.

In addition, the fact it's sliding down rails rather than hanging in
free space may alter the efficiency of the mechanism.

Yes. A simple thought experiment works here. It clearly requires less
energy to push a wheeled object horizontally than it does to lift it
vertically. So there's clearly also a continuum between 0 degrees = least
energy and 90 degrees (from the horizontal) = most energy, and therefore
something like 45 degrees = somewhere in between the two.

Which, in turn increases the distance that it requires to be propelled.