Mechanical Engineering/Escalator Design.

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Escalator
Escalator  
Escalator
Escalator  
QUESTION: Dear Michael

http://en.wikipedia.org/wiki/Escalator
http://science.howstuffworks.com/transport/engines-equipment/escalator.htm
http://www.reedconstructiondata.com/documents/FS/specdata/143100_10001243_01_SD_


Escalators, like moving walkways, are powered by constant-speed alternating current motors and move at approximately 12 feet (0.300.61 m) per second. The typical angle of inclination of an escalator to the horizontal floor level is 30 degrees with a standard rise up to about 60 feet (18 m).

1. Is the Angle of inclination of 30 degree standard to the Horizontal floor and standard rise of about 60 feet standardized in all escalator designs  while manufacturing ?. i.e. Can the Angle of inclination differ to 45 degree or standard rise to say 80 meters
or speed vary i.e.  2-3 feet (0.61 m - 0.91 m) per second ?.

2. Is the Load carrying capacity (weight of the Riders) in a escalator set to a maximum limit ?. i.e. Every Escalator designed
has a maximum load carrying capacity similar to a Elevator device ?

In this case, how safety of the passengers is ensured if overload happens ?. what is the overload protection mechanism
inbuilt within the escalator ?. As soon as there is a overload of
extra weight, the escalator device stops moving upwards (Step Up Motion) or downwards (Step Down Motion) ?.

3. In events of electric power breakdowns where escalator comes to a standstill, how passengers safety is ensured as they may lose their balance while moving up or down ?. Is the escalator machine
battery powered up in case of mains power failure ?.
  
Awaiting your reply,

Thanks & Regards,
Prashant S Akerkar

ANSWER: The angle of inclination is built depending on the codes of the local authority.  Usually, from my understanding, they are built to the same rise/run of a standard staircase.  As for the speed, I'm sure there is a local code that states it.

Load capacity is dependent on the length etc.  You can increase the load capacity of the unit by increasing the HP of the motor and adjusting the belting style.

Overload would be handled by a clutch to prevent the unit from moving backwards.

Electric breakdown is also controlled by the clutch to prevent the unit from moving backwards.  It would have to be a soft clutch to allow a small amount of slip in the system to keep the inertial forces from causing the riders from losing balance.  Battery power would be feasible to keep the unit running but would be a very large battery system.

---------- FOLLOW-UP ----------

Skywalk
Skywalk  

Horizontal Auto-Walk
Horizontal Auto-Walk  
QUESTION: Dear Michael

Thank you.

1. if a Comparison between Escalator and Elevator Systems is done in terms of  Manufacturing, Installation, Maintenance Costs, Escalators will
be more expensive (i.e. Cost incurred for Manufacturing, Installing and Maintenance) than Elevators ?

2. Can we implement Escalators in already built structures viz Shopping Malls, Departmental stores, Buildings, Airports, Metro Rails etc.

i.e. The Shopping malls, Departmental Stores, Airports, Metro rails, Buildings
are already constructed sites and not a new construction site.

3. Do you feel Specific Sky walks if replaced by Horizontal Auto walks could be more useful for people flow ?

http://en.wikipedia.org/wiki/Mumbai_Skywalk_Project

Awaiting your reply,

Thanks & Regards,
Prashant S Akerkar

Answer
1. if a Comparison between Escalator and Elevator Systems is done in terms of  Manufacturing, Installation, Maintenance Costs, Escalators will
be more expensive (i.e. Cost incurred for Manufacturing, Installing and Maintenance) than Elevators ?

In my opinion I believe that an Escalator would be less expensive due to the consistent movement and lack of wear compared to teh cables etc.  Also, there would be significantly lower costs in insurance (in my opinion)

2. Can we implement Escalators in already built structures viz Shopping Malls, Departmental stores, Buildings, Airports, Metro Rails etc.

i.e. The Shopping malls, Departmental Stores, Airports, Metro rails, Buildings
are already constructed sites and not a new construction site.

This would be about the same as installing a stairway, there would be permits etc, but is definitely feasible.

3. Do you feel Specific Sky walks if replaced by Horizontal Auto walks could be more useful for people flow ?

As for  the skywalks, I'm not sure what a horizontal auto walk would be... is that like the moving walkways in an airport?  

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Michael Aschenbrener

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