On 2015\11\14 16:18, wrote:

Is there any place on the Greenford Branch Line London, or anywhere else
in London, that continue to use semaphores?

The Dudding Hill Line, unless its been resignalled since June.

Basil Jet wrote:

https://www.youtube.com/watch?v=sxScXvX1Dv4

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?

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

Chris J Dixon wrote:
Basil Jet wrote:

https://www.youtube.com/watch?v=sxScXvX1Dv4

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?

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. I assume it has
a counterbalance like a normal lift? I'll see if I can tell when I go to
see it on Monday. Of course, the balance weight may be hidden, as it is
with many normal lifts.

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.

--
Clive D.W. Feather | Home:
Mobile: +44 7973 377646 | Web: http://www.davros.org
Please reply to the Reply-To address, which is:

Clive D. W. Feather wrote:
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.

I assume it runs on rollers or guide wheels, rather than sliding. It's at
quite a shallow angle.
See http://democracy.walthamforest.gov.u...pendix%20B.pdf

In message
-sept
ember.org, Recliner wrote:
In addition, the fact it's sliding down rails rather than hanging in
free space may alter the efficiency of the mechanism.

I assume it runs on rollers or guide wheels, rather than sliding.

Bad wording on my part.

It's at
quite a shallow angle.

With a few exceptions, LU escalators are at 30 degrees, so presumably
this is as well.

--
Clive D.W. Feather | Home:
Mobile: +44 7973 377646 | Web: http://www.davros.org
Please reply to the Reply-To address, which is:

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.

Mark
--
Insert random witticism here
http://www.markgoodge.com

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.

If you ignore friction, it takes zero net energy to move an object at a
fixed speed horizontally, and a fixed amount to lift it a particular
distance. But the *power* will be less if you lift it more slowly, which
the inclined lift does, compared to a typical vertical lift. Of course,
friction isn't zero, and will be more, the shallower the angle. But if the
lift box runs on wheels on rails, the friction will be low.

In message e.net, at
10:29:44 on Sat, 14 Nov 2015, Mark Goodge
remarked:
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.

If it's the same weight, and with the same frictional losses as a
conventional lift, it would take the same energy to make the journey
[gaining potential energy in the process].

If the journey takes longer, the *power* (energy/time) would be less.

But it's complicated by the presence (or absence) of a counterweight,
which transfers its energy to the lift (and vice versa).

What the chap in the video is probably saying is that (without having
really thought about the physics himself) that the wattage plate on the
motor is less than you'd expect to find on a lift motor.
--
Roland Perry

On 2015\11\14 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.

Your basic task is to get someone from ground level to platform level.
You have to compare doing it vertically with doing it in a LONGER
diagonal shaft. Comparing 10 metres vertical with 10 metres at an angle
is meaningless. There is a counterbalance, but I imagine that matches
the weight of a half-laden cabin, so there will still be weight to be
moved most of the time. I imagine the friction in an angled lift will
massively exceed the friction in a vertical lift.

The lift is ridiculously over-engineered. A platform with shoulder
height gates would have done the job, instead of this cuboid with
electronic displays all over it and lights in the ceiling. Lifts are
cuboids because if something snaps, you don't want it crashing down on
the heads of the people. There is nothing above an inclinator to snap
and land on people, so no roof necessary, and no lights required either.
Typical public sector largesse... no private company would have done this.